142-479: Several naval ships of Germany were named Bremse after the horse-fly ( German : Bremse ): Horse-fly Horse-flies and deer flies are true flies in the family Tabanidae in the insect order Diptera . The adults are often large and agile in flight. Only female horseflies bite land vertebrates, including humans, to obtain blood . They prefer to fly in sunlight, avoiding dark and shady areas, and are inactive at night. They are found all over
284-418: A bite to not be noticed by the host at the time, bites from tabanids are immediately irritating to the victim, so that they are often brushed off, and may have to visit multiple hosts to obtain sufficient blood. This behaviour means that they may carry disease-causing organisms from one host to another. Large animals and livestock are generally powerless to dislodge the fly, so there is no selective advantage for
426-732: A blood meal before they are able to reproduce effectively. To obtain the blood, the females, but not the males, bite animals, including humans. The female needs about six days to fully digest her blood meal and after that, she needs to find another host. The flies seem to be attracted to a potential victim by its movement, warmth, and surface texture, and by the carbon dioxide it breathes out. The flies mainly choose large mammals such as cattle, horses, camels, and deer, but few are species-specific. They have also been observed feeding on smaller mammals, birds, lizards, and turtles, and even on animals that have recently died. Unlike many biting insects such as mosquitoes , whose biting mechanism and saliva allow
568-440: A body length between 5 and 25 mm (0.2 and 1.0 in), with the largest having a wingspan of 60 mm (2.4 in). Deer flies in the genus Chrysops are up to 10 mm (0.4 in) long, have yellow to black bodies and striped abdomens, and membranous wings with dark patches. Horse-flies (genus Tabanus ) are larger, up to 25 mm (1 in) in length and are mostly dark brown or black, with dark eyes, often with
710-511: A common ancestor, the archediction represents the "template" that has been modified (and streamlined) by natural selection for 200 million years. According to current dogma, the archedictyon contained six to eight longitudinal veins. These veins (and their branches) are named according to a system devised by John Comstock and George Needham—the Comstock-Needham system: The costa (C) is the leading marginal vein on most insects, although
852-450: A common tracheal stem in nymphal insects, and the veins are regarded as branches of a single anal vein. Distally, the vannal veins are either simple or branched. The jugal vein (J) of the jugal lobe of the wing is often occupied by a network of irregular veins, or it may be entirely membranous; sometimes it contains one or two distinct, small veins, the first jugal vein, or vena arcuata, and the second jugal vein, or vena cardinalis (2J). All
994-426: A female. Tabanids are found worldwide, except for the polar regions, but they are absent from some islands such as Greenland , Iceland , and Hawaii . The genera Tabanus , Chrysops , and Haematopota all occur in temperate, subtropical, and tropical locations, but Haematopota is absent from Australia and South America. They mostly occur in warm areas with suitable moist locations for breeding, but also occupy
1136-488: A flat plate, the stipes, hinged to the cardo . Both cardo and stipes are loosely joined to the head by a membrane, so they are capable of movement. Distally on the stipes are two lobes, an inner lacinea, and an outer galea, one or both of which may be absent. More laterally on the stipes is a jointed, leglike palp made up of many segments; in Orthoptera, there are five. Anterior and posterior rotator muscles are inserted on
1278-569: A fossil insect that has elongated mouthparts is not necessarily a bloodsucker, as it may instead have fed on nectar. The ancestral tabanids may have co-evolved with the angiosperm plants on which they fed. With a necessity for high-protein food for egg production, the diet of early tabanomorphs was probably predatory, and from this, the bloodsucking habit may have evolved. In the Santana Formation in Brazil, no mammals have been found, so
1420-422: A hardened proteinaceous matrix, which forms much of the exoskeleton . In its pure form, it is leathery, but when encrusted in calcium carbonate , it becomes much harder. The difference between the unmodified and modified forms is evident when comparing the body wall of a caterpillar (unmodified) to a beetle (modified). From the embryonic stages, a layer of columnar or cuboidal epithelial cells gives rise to
1562-443: A metallic sheen. Yellow flies (genus Diachlorus ) are similar in shape to deer flies, but have yellowish bodies and the eyes are purplish-black with a green sheen. Some species in the subfamily Pangoniinae have an exceptionally long proboscis (tubular mouthpart). The larvae are long and cylindrical or spindle-shaped with small heads and 12 body segments. They have rings of tubercles (warty outgrowths) known as pseudopods around
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#17327717319131704-401: A pair of segmented palps. The mouthparts and rest of the head can be articulated in at least three different positions: prognathous, opisthognathous, and hypognathous. In species with prognathous articulation, the head is vertically aligned with the body, such as species of Formicidae ; while in a hypognathous type, the head is aligned horizontally adjacent to the body. An opisthognathous head
1846-399: A particular nuisance near swimming pools. Since tabanids prefer to be in sunshine, they normally avoid shaded places such as barns, and are inactive at night. Attack patterns vary with species; clegs fly silently and prefer to bite humans on the wrist or bare leg; large species of Tabanus buzz loudly, fly low, and bite ankles, legs, or backs of knees; Chrysops flies somewhat higher, bites
1988-409: A partitioned cylinder in the center of which the larva settled to pupate after closing the entrance; this adaption protects the pupae against mudcracks when the mud dries up, as a spreading crack would change direction when it hit the wall of the cylinder. The pupae are brown and glossy, rounded at the head end, and tapering at the other end. Wing and limb buds can be seen and each abdominal segment
2130-404: A posterior concave branch. The convex or concave nature of the veins has been used as evidence in determining the identities of the persisting distal branches of the veins of modern insects, but it has not been demonstrated to be consistent for all wings. Wing areas are delimited and subdivided by fold lines , along which the wings can fold, and flexion lines , which flex during flight. Between
2272-426: A reticulum as in the wings of Odonata (dragonflies and damselflies) and at the base of the forewings of Tettigonioidea and Acridoidea (katydids and grasshoppers, respectively). The archedictyon is the name given to a hypothetical scheme of wing venation proposed for the very first winged insect. It is based on a combination of speculation and fossil data. Since all winged insects are believed to have evolved from
2414-426: A sandwich pattern, while the exocuticle is rigid and sclerotized . The exocuticle is greatly reduced in many soft-bodied insects, especially the larval stages (e.g., caterpillars ). Chemically, chitin is a long-chain polymer of a N-acetylglucosamine , a derivative of glucose. In its unmodified form, chitin is translucent, pliable, and resilient. In arthropods , however, it is often modified, becoming embedded in
2556-594: A single compound eye of, for example, large dragonflies. This type of eye gives less resolution than eyes found in vertebrates, but it gives an acute perception of movement and usually possesses UV- and green sensitivity, and may have additional sensitivity peaks in other regions of the visual spectrum. Often an ability to detect the E-vector of polarized light exists in polarization of light. There can also be an additional two or three ocelli, which help detect low light or small changes in light intensity. The image perceived
2698-443: A single day to tabanid flies, a loss which can weaken or even kill them. Anecdotal reports of bites leading to fatal anaphylaxis in humans have been made, an extremely rare occurrence. Control of tabanid flies is difficult. Malaise traps are most often used to capture them, and these can be modified with the use of baits and attractants that include carbon dioxide or octenol . A dark shiny ball suspended below them that moves in
2840-429: A small vein, the precosta, is sometimes found above the costa. In almost all extant insects, the precosta is fused with the costa; the costa rarely ever branches because it is at the leading edge, which is associated at its base with the humeral plate. The trachea of the costal vein is perhaps a branch of the subcostal trachea. Located after the costa is the third vein, the subcosta, which branches into two separate veins:
2982-430: A stout stabbing organ with two pairs of sharp cutting blades, and a spongelike part used to lap up the blood that flows from the wound. The larvae are predaceous and grow in semiaquatic habitats. Female horse-flies can transfer blood-borne diseases from one animal to another through their feeding habit. In areas where diseases occur, they have been known to carry equine infectious anaemia virus , some trypanosomes ,
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#17327717319133124-603: A study comparing horse-fly behaviour when approaching horses wearing either striped or check-patterned rugs, when compared with plain rugs, found that both patterns were equally effective in deterring the insects. Mating often occurs in swarms, generally at landmarks such as hilltops . The season, time of day, and type of landmark used for mating swarms are specific to particular species. Eggs are laid on stones or vegetation near water, in clusters of up to 1000, especially on emergent water plants. The eggs are white at first but darken with age. They hatch after about six days, with
3266-445: A tabanid with a blue-black abdomen common to the southeastern United States. Paul Muldoon ’s chapbook Binge contains a poem "Clegs and Midges" which uses gadflies, real and metaphoric, "cleg" being a British term for the horse-fly. In Norse mythology Loki took the form of a gadfly to hinder Brokkr during the manufacture of the hammer Mjölnir , weapon of Thor (Hammer of Thor). Insect morphology#Head Insect morphology
3408-406: A variety of different sclerites and sutures, varying greatly from order to order, and they will not be discussed in detail in this section. Most phylogenetically advanced insects have two pairs of wings located on the second and third thoracic segments. Insects are the only invertebrates to have developed flight capability, and this has played an important part in their success. Insect flight
3550-407: A vein forks there is always an interpolated vein of the opposite position between the two branches. The concave vein will fork into two concave veins (with the interpolated vein being convex) and the regular alteration of the veins is preserved. The veins of the wing appear to fall into an undulating pattern according to whether they tend to fold up or down when the wing is relaxed. The basal shafts of
3692-457: A very hard, stiff, and well-compacted sting, with which he strikes through the Oxe his hide; he is in fashion like a great Fly, and forces the beasts for fear of him only to stand up to the belly in water, or else to betake themselves to wood sides, cool shades, and places where the wind blows through." The " Blue Tail Fly " in the eponymous song was probably the mourning horsefly ( Tabanus atratus ),
3834-537: A wide range of habitats from deserts to alpine meadows. They are found from sea level to at least 3,300 m (10,800 ft). The oldest records of the family come from the Early Cretaceous , with the oldest record being Eotabanoid , known from wings found in the Berriasian (145–140 million years ago) Purbeck Group of England. Although the bloodsucking habit is associated with a long proboscis,
3976-422: Is a combination of inputs from the numerous ommatidia, located on a convex surface, thus pointing in slightly different directions. Compared with simple eyes , compound eyes possess very large view angles and better acuity than the insect's dorsal ocelli, but some stemmatal (= larval eyes), for example, those of sawfly larvae ( Tenthredinidae ) with an acuity of 4 degrees and very high polarization sensitivity, match
4118-433: Is a landmark on the posterior surface of the head, and is typically near the occipital foremen. In pterygotes, the postocciput forms the extreme posterior, often U-shaped, which forms the rim of the head extending to the postoccipital suture. In pterygotes, such as those of Orthoptera, the occipital foramen and the mouth are not separated. The three types of occipital closures, or points under the occipital foramen that separate
4260-423: Is a median lobe immediately behind the mouth, projecting forwards from the back of the preoral cavity; it is a lobe of uncertain origin, but perhaps associated with the mandibular segment; in apterygotes, earwigs, and nymphal mayflies, the hypopharynx bears a pair of lateral lobes, the superlinguae (singular: superlingua). It divides the cavity into a dorsal food pouch, or cibarium, and a ventral salivarium into which
4402-434: Is between the compound eyes, clypeus, and mouthparts. The postgena is the area immediately posteriad, or posterior or lower on the gena of pterygote insects , and forms the lateral and ventral parts of the occipital arch. The occipital arch is a narrow band forming the posterior edge of the head capsule arching dorsally over the foramen. The subgenal area is usually narrow, located above the mouthparts; this area also includes
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4544-405: Is called the tergum (or notum, to distinguish it from the abdominal terga). The two lateral regions are called the pleura (singular: pleuron), and the ventral aspect is called the sternum. In turn, the notum of the prothorax is called the pronotum, the notum for the mesothorax is called the mesonotum and the notum for the metathorax is called the metanotum. Continuing with this logic, there are also
4686-477: Is continuously sclerotized with the latter. The cubitus, the sixth vein of the wing, is primarily two-branched. The primary forking takes place near the base of the wing, forming the two principal branches (Cu1, Cu2). The anterior branch may break up into several secondary branches, but commonly it forks into two distal branches. The second branch of the cubitus (Cu2) in Hymenoptera, Trichoptera, and Lepidoptera,
4828-414: Is fringed with short spines. After about two weeks, metamorphosis is complete, the pupal case splits along the thorax, and the adult fly emerges. Males usually appear first, but when both sexes have emerged, mating takes place, courtship starting in the air and finishing on the ground. The female needs to feed on blood before depositing her egg mass. Eggs are often attacked by tiny parasitic wasps , and
4970-435: Is innervated by the tritocerebrum of the brain, which is the fused ganglia of the third head segment. This is formed from the fusion of parts of a pair of ancestral appendages found on the third head segment, showing their relationship. Its ventral, or inner, surface is usually membranous and forms the lobe-like epipharynx, which bears mechanosensilla and chemosensilla. Chewing insects have two mandibles, one on each side of
5112-438: Is inwardly concave, thus forming a central tube through which moisture is sucked. Suction is affected by the contraction and expansion of a sac in the head. The proboscis is coiled under the head when the insect is at rest and is extended only when feeding. The maxillary palpi are reduced or even vestigial. They are conspicuous and five-segmented in some of the more basal families and are often folded. The shape and dimensions of
5254-466: Is known as deer flies, perhaps because of their abundance on moorland where deer roam, and buffalo-flies, moose-flies and elephant-flies emanate from other parts of the world where these animals are found. The term "horse-fly" refers primarily to Tabaninae that are typically larger and stouter, and that lack the banded wings deer flies have. Other common names include tabanids , gadflies , green-headed flies , and green flies . The word "Tabanus"
5396-450: Is longitudinally placed on the vertex, separating the epicranial halves of the head to the left and right sides. Depending on the insect, the suture may come in different shapes: like either a Y, U or V. Those diverging lines that make up the ecdysial suture are called the frontal or frontogenal sutures. Not all species of insects have frontal sutures, but in those that do, the sutures split open during ecdysis , which provides an opening for
5538-417: Is not helpful. In the anatomy of some taxa, such as many Cicadomorpha , the front of the head is fairly clearly distinguished and tends to be broad and sub-vertical; that median area commonly is taken to be the frons. The clypeus is a sclerite between the face and labrum, which is dorsally separated from the frons by the frontoclypeal suture in primitive insects. The clypeogenal suture laterally demarcates
5680-571: Is not very well understood, relying on turbulent aerodynamic effects. The primitive insect groups use muscles that act directly on the wing structure. The more advanced groups making up the Neoptera have foldable wings, and their muscles act on the thorax wall and power the wings indirectly. These muscles can contract multiple times for each single nerve impulse, allowing the wings to beat faster than would ordinarily be possible. Insect flight can be rapid, maneuverable, and versatile, possibly due to
5822-485: Is positioned diagonally, such as in species of Blattodea and some Coleoptera . The mouthparts vary greatly between insects of different orders, but the two main functional groups are mandibulate and haustellate. Haustellate mouthparts are used for sucking liquids and can be further classified by the presence of stylets , which include piercing-sucking, sponging, and siphoning. The stylets are needle-like projections used to penetrate plant and animal tissues. The stylets and
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5964-444: Is reabsorbed. In molting, the old cuticle separates from the epidermis ( apolysis ). Enzymatic molting fluid is then released between the old cuticle and epidermis, which separates the exocuticle by digesting the endocuticle and sequestering its material for the new cuticle. When the new cuticle has formed sufficiently, the epicuticle and reduced exocuticle are shed in ecdysis . The four principal regions of an insect body segment are
6106-416: Is similar in structure to the maxilla , but with the appendages of the two sides fused by the midline, so they come to form a median plate. The basal part of the labium, equivalent to the maxillary cardines and possibly including a part of the sternum of the labial segment, is called the postmentum. This may be subdivided into a proximal submentum and a distal mentum. Distal to the postmentum, and equivalent to
6248-406: Is the study and description of the physical form of insects . The terminology used to describe insects is similar to that used for other arthropods due to their shared evolutionary history. Three physical features separate insects from other arthropods: they have a body divided into three regions (called tagmata) (head, thorax, and abdomen), three pairs of legs, and mouthparts located outside of
6390-638: Is thrust downwards and the stylets slice into the flesh. Some of these have sawing edges and muscles can move them from side-to-side to enlarge the wound. Saliva containing anticoagulant is injected into the wound to prevent clotting. The blood that flows from the wound is lapped up by another mouthpart which functions as a sponge. Bites can be painful for a day or more; fly saliva may provoke allergic reactions such as hives and difficulty with breathing. Tabanid bites can make life outdoors unpleasant for humans, and can reduce milk output in cattle. They are attracted by polarized reflections from water, making them
6532-458: Is usually triangular in shape, and its veins typically spread out from the third axillary like the ribs of a fan. Some of the vannal veins may be branched, and secondary veins may alternate with the primary veins. The vannal region is usually best developed in the hindwing, in which it may be enlarged to form a sustaining surface, as in Plecoptera and Orthoptera. The great fan-like expansions of
6674-400: Is usually unbranched; primitively, it is two-branched. The vannal veins (lV to nV) are the anal veins immediately associated with the third axillary, and are directly affected by the movement of this sclerite that brings about the flexion of the wings. In number, the vannal veins vary from one to 12, according to the expansion of the vannal area of the wing. The vannal tracheae usually arise from
6816-573: The Actium battlefield to that of a cow chased by a gadfly: "The breeze [gadfly] upon her, like a cow in June / hoists sail and flies", where "June" may allude not only to the month but also to the goddess Juno , who torments Io, and the cow in turn may allude to Io, who is changed into a cow in Ovid 's Metamorphoses . The physician and naturalist Thomas Muffet wrote that the horse-fly "carries before him
6958-441: The cuticle , consists of two layers; the epicuticle , which is a thin, waxy, water-resistant outer layer that lacks chitin, and the layer under it is called the procuticle . This is chitinous and much thicker than the epicuticle and has two layers, the outer is the exocuticle while the inner is the endocuticle. The tough and flexible endocuticle is built from numerous layers of fibrous chitin and proteins, crisscrossing each other in
7100-546: The equine infectious anaemia virus and various species of Trypanosoma which cause diseases in animals and humans. Species of the genus Chrysops transmit the parasitic filarial worm Loa loa between humans, and tabanids are known to transmit anthrax among cattle and sheep, and tularemia between rabbits and humans. Blood loss is a common problem in some animals when large flies are abundant. Some animals have been known to lose up to 300 ml (11 imp fl oz; 10 US fl oz) of blood in
7242-505: The filarial worm Loa loa , anthrax among cattle and sheep, and tularemia . They can reduce growth rates in cattle and lower the milk output of cows if suitable shelters are not provided. Horse-flies have appeared in literature ever since Aeschylus in Ancient Greece mentioned them driving people to "madness" through their persistent pursuit. Tabanidae are known by a large number of common names. The subfamily Chrysopsinae
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#17327717319137384-548: The head capsule . This position of the mouthparts divides them from their closest relatives, the non-insect hexapods , which include Protura , Diplura , and Collembola . There is enormous variation in body structure amongst insect species. Individuals can range from 0.3 mm ( fairyflies ) to 30 cm across ( great owlet moth ); have no eyes or many; well-developed wings or none; and legs modified for running, jumping, swimming, or even digging. These modifications allow insects to occupy almost every ecological niche except
7526-406: The honey bee ( Hymenoptera : Apidae : Apis mellifera ), the elongated and fused labial glossae form a hairy tongue, which is surrounded by the maxillary galeae and the labial palps to form a tubular proboscis containing a food canal. In feeding, the tongue is dipped into the nectar or honey, which adheres to the hairs, and then is retracted so the adhering liquid is carried into the space between
7668-409: The hypostoma and pleurostoma . The vertex extends anteriorly above the bases of the antennae as a prominent, pointed, concave rostrum. The posterior wall of the head capsule is penetrated by a large aperture, the foramen. Through it passes the organ systems, such as the nerve cord , esophagus , salivary ducts , and musculature , connecting the head with the thorax . On the posterior aspect of
7810-472: The superfamily Tabanoidea . Along with the Rhagionoidea, this superfamily makes up the infraorder Tabanomorpha . Tabanoid families seem to be united by the presence of a venom canal in the mandible of the larvae. Worldwide, about 4,455 species of Tabanidae have been described , over 1,300 of them in the genus Tabanus . Tabanid identification is based mostly on adult morphological characters of
7952-593: The tergum or dorsal, sternum or ventral, and the two pleura or laterals. Hardened plates in the exoskeleton are called sclerites, which are subdivisions of the major regions – tergites, sternites, and pleurites, for respective regions tergum, sternum, and pleuron. The head in most insects is enclosed in a hard, heavily sclerotized, exoskeletal head capsule . The main exception is in those species whose larvae are not fully sclerotized, mainly some holometabola; but even most unsclerotized or weakly sclerotized larvae tend to have well-sclerotized head capsules, for example,
8094-634: The Australian March flies, are known for being extremely noisy during flight, though clegs, for example, fly quietly and bite with little warning. Tabanids are agile fliers; Hybomitra species have been observed to perform aerial manoeuvres similar to those performed by fighter jets, such as the Immelmann turn . Horseflies can lay claim to being the fastest flying insects; the male Hybomitra hinei wrighti has been recorded reaching speeds of up to 145 kilometres per hour (90 mph) when pursuing
8236-698: The Scionini also being monophyletic apart from the difficult-to-place genus Goniops . Adersia was recovered within the Pangoniini as were the genera previously placed in the Scepcidinae, and Mycteromyia and Goniops were recovered within the Chrysopsini. The Tabaninae lack ocelli (simple eyes) and have no spurs on the tips of their hind tibiae . In the Pangoniinae, ocelli are present and
8378-669: The Tabanidae and moved into the Rhagionidae before being elevated into a separate family. The infraorder Tabanomorpha shares the blood-feeding habit as a common primitive characteristic, although this is restricted to the female. Two well-known genera are the common horse-flies, Tabanus , named by Swedish taxonomist Carl Linnaeus in 1758, and the deer flies, Chrysops , named by the German entomologist Johann Wilhelm Meigen in 1802. Meigen did pioneering research on flies and
8520-529: The addition of zinc, manganese, or rarely, iron, in amounts up to about 4% of the dry weight. They are typically the largest mouthparts of chewing insects, being used to masticate (cut, tear, crush, chew) food items. They open outwards (to the sides of the head) and come together medially. In carnivorous, chewing insects, the mandibles can be modified to be more knife-like, whereas in herbivorous chewing insects, they are more typically broad and flat on their opposing faces (e.g., caterpillars ). In male stag beetles ,
8662-407: The anal area can be folded like a fan. The four different fields found on insect wings are: Most veins and cross-veins occur in the anterior area of the remigium , which is responsible for most of the flight, powered by the thoracic muscles. The posterior portion of the remigium is sometimes called the clavus; the two other posterior fields are the anal and jugal areas . When the vannal fold has
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#17327717319138804-478: The antecostal sutures, marking the primary intersegmental folds between segments; phragmata provide attachment for the longitudinal flight muscles. Each alinotum (sometimes confusingly referred to as a "notum") may be traversed by sutures that mark the position of internal strengthening ridges and commonly divide the plate into three areas: the anterior prescutum, the scutum, and the smaller posterior scutellum. The lateral pleural sclerites are believed to be derived from
8946-436: The antennae is also quite variable, but the first segment (the one attached to the head) is always called the scape, and the second segment is called the pedicel. The remaining antennal segments or flagellomeres are called the flagellum. General insect antenna types are shown below: The insect mouthparts consist of the maxilla, labium, and in some species, the mandibles. The labrum is a simple, fused sclerite, often called
9088-446: The antennae is pointed and annulated, appearing to be composed of several tapering rings. There are no hairs or arista stemming from the antennae. Both the head and thorax are clad in short hairs, but no bristles are on the body. The membranous forewings are clear, either shaded uniformly grey or brown, or patterned in some species; they have a basal lobe (or calypter) that covers the modified knob-like hindwings or halteres . The tips of
9230-575: The antennal flagellum (whip-like structure) usually has eight annuli (or rings). In the Chrysopsinae, the antennal flagellum has a basal plate and the flagellum has four annuli. Females have a shining callus on the frons (front of the head between the eyes). The Adersiinae have a divided tergite on the ninth abdominal segment, and the Scepsidinae have highly reduced mouthparts. Members of the family Pelecorhynchidae were initially included in
9372-463: The anterior and posterior. The base of the subcosta is associated with the distal end of the neck of the first axillary. The fourth vein is the radius, which is branched into five separate veins. The radius is generally the strongest vein of the wing. Toward the middle of the wing, it forks into a first undivided branch (R1) and a second branch, called the radial sector (Ra), which subdivides dichotomously into four distal branches (R2, R3, R4, R5). Basally,
9514-413: The back of the neck, and has a high buzzing note. The striped hides of zebras may have evolved to reduce their attractiveness to horse-flies and tsetse flies . The closer together the stripes, the fewer flies are visually attracted; the zebra's legs have particularly fine striping, and this is the shaded part of the body that is most likely to be bitten in other, unstriped equids. More recent research by
9656-407: The blood from clotting. And finally, the labrum (upper lip) is used to suck up the blood. Species of the genus Anopheles are characterized by their long palpi (two parts with widening end), almost reaching the end of labrum. The proboscis is formed from maxillary galeae and is an adaption found in some insects for sucking. The muscles of the cibarium or pharynx are strongly developed and form
9798-430: The breeze can also attract them and forms a key part of a modified "Manitoba trap" that is used most often for trapping and sampling the Tabanidae. Cattle can be treated with pour-on pyrethroids which may repel the flies, and fitting them with insecticide-impregnated eartags or collars has had some success in killing the insects. Tabanid bites can be painful to humans. Usually, a weal (raised area of skin) occurs around
9940-420: The cardo, and ventral adductor muscles arising on the tentorium are inserted on both the cardo and stipes. Arising in the stipes are flexor muscles of the lacinea and galea and another lacineal flexor arises in the cranium, but neither the lacinea nor the galea has an extensor muscle. The palp has levator and depressor muscles arising in the stipes, and each segment of the palp has a single muscle causing flexion of
10082-416: The changing shape, extraordinary control, and variable motion of the insect wing. Insect orders use different flight mechanisms; for example, the flight of a butterfly can be explained using steady-state, nontransitory aerodynamics , and thin airfoil theory. Each of the wings consists of a thin membrane supported by a system of veins. The membrane is formed by two layers of integument closely apposed, while
10224-495: The clypeus, with the clypeus ventrally separated from the labrum by the clypeolabral suture. The clypeus differs in shape and size, such as species of Lepidoptera with a large clypeus with elongated mouthparts. The cheek or gena forms the sclerotized area on each side of the head below the compound eyes extending to the gular suture. Like many parts making up the insect's head, the gena varies among species, with its boundaries difficult to establish. In dragonflies and damselflies , it
10366-439: The clypeus. Laterally it is limited by the fronto-genal sulcus, if present, and the boundary with the vertex, by the ecdysial cleavage line, if it is visible. If there is a median ocellus, it generally is on the frons, though in some insects such as many Hymenoptera, all three ocelli appear on the vertex. A more formal definition is that it is the sclerite from which the pharyngeal dilator muscles arise, but in many contexts that too,
10508-419: The deep ocean. This article describes the basic insect body and some variations of the different body parts; in the process, it defines many of the technical terms used to describe insect bodies. Insects, like all arthropods, have no interior skeleton; instead, they have an exoskeleton , a hard outer layer made mostly of chitin that protects and supports the body. The insect body is divided into three parts :
10650-420: The emerging larvae using a special hatching spike to open the egg case. The larvae fall into the water or onto the moist ground below. Chrysops species develop in particularly wet locations, while Tabanus species prefer drier places. The larvae are legless grubs, tapering at both ends. They have small heads and 11 or 13 segments and moult six to 13 times over the course of a year or more. In temperate species,
10792-407: The external cuticle and an internal basement membrane. The majority of insect material is inside of the endocuticle. The cuticle provides muscular support and acts as a protective shield as the insect develops. However, since it cannot grow, the external sclerotized part of the cuticle is periodically shed in a process called "molting". As the time for molting approaches, most of the exocuticle material
10934-404: The external organs of the respiratory system, are found on the pterothorax, usually one between the pro- and mesopleoron, as well as one between the meso- and metapleuron. The ventral view or sternum follows the same convention, with the prosternum under the prothorax, the mesosternum under the mesothorax and the metasternum under the metathorax. The notum, pleura, and sternum of each segment have
11076-463: The families Bombyliidae and Tachinidae, and Hymenoptera in the family Pteromalidae . When fully developed, the larvae move into drier soil near the surface of the ground to pupate . In dry places a "remarkable" adaptation was discovered in the 1920s by W.A. Lamborn in Malawi (then Nyasaland ). The larvae were discovered to tunnel in a spiral motion while the mud was still wet and plastic, forming
11218-406: The feeding tube form the modified mandibles, maxilla, and hypopharynx. Mandibular mouthparts are found in species of Odonata , adult Neuroptera , Coleoptera , Hymenoptera , Blattodea , Orthoptera , and Lepidoptera . However, most adult Lepidoptera have siphoning mouthparts, while their larvae (commonly called caterpillars ) have mandibles . The labrum is a broad lobe forming the roof of
11360-547: The fine hairs ( setae ) that cover them. However, touch is not the only thing that antennae can detect; numerous tiny sensory structures on the antennae allow insects to sense smells, temperature, humidity, pressure, and even potentially sense themselves in space . Some insects, including bees and some groups of flies, can also detect sound with their antennae. The number of segments in an antenna varies amongst insects, with higher flies having 3-6 segments, while adult cockroaches can have over 140. The general shape of
11502-410: The first vannal vein. In the cicada, the vannal fold lies immediately behind the first vannal vein (lV). These small variations in the actual position of the vannal fold, however, do not affect the unity of action of the vannal veins, controlled by the flexor sclerite (3Ax), in the flexion of the wing. In the hindwings of most Orthoptera, a secondary vena dividens forms a rib in the vannal fold. The vannus
11644-437: The flexion and the fold lines, the fundamental distinction is often blurred, as fold lines may permit some flexibility or vice versa. Two constants, found in nearly all insect wings, are the claval (a flexion line) and jugal folds (or fold line), forming variable and unsatisfactory boundaries. Wing folding can be very complicated, with transverse folding occurring in the hindwings of Dermaptera and Coleoptera, and in some insects,
11786-400: The flies to evolve a less immediately painful bite. The mouthparts of females are of the usual dipteran form and consist of a bundle of six chitinous stylets that, together with a fold of the fleshy labium , form the proboscis . On either side of these are two maxillary palps. When the insect lands on an animal, it grips the surface with its clawed feet, the labium is retracted, the head
11928-404: The fossil tabanids found there likely fed on reptiles. Cold bloodsucking probably preceded warm bloodsucking, but some dinosaurs are postulated to have been warm-blooded and may have been early hosts for the horse-flies. The Tabanidae are true flies and members of the insect order Diptera. With the families Athericidae , Pelecorhynchidae and Oreoleptidae , Tabanidae are classified in
12070-413: The fused maxillary stipites, is the prementum. The prementum closes the preoral cavity from behind. Terminally, it bears four lobes, two inner glossae, and two outer paraglossae, which are collectively known as the ligula. One or both pairs of lobes may be absent or they may be fused to form a single median process. A palp arises from each side of the prementum, often being three-segmented. The hypopharynx
12212-450: The galeae and labial palps. This back-and-forth glossal movement occurs repeatedly. Movement of liquid to the mouth results from the action of the cibarial pump, facilitated by each retraction of the tongue pushing liquid up the food canal either for feeding requirements or to have a suitable media for laying their egg. The insect thorax has three segments: the prothorax , mesothorax , and metathorax . The anterior segment, closest to
12354-400: The group of vannal tracheae. In the mature wings of more generalized insects, the postcubitus is always associated proximally with the cubitus and is never intimately connected with the flexor sclerite (3Ax) of the wing base. In Neuroptera, Mecoptera, and Trichoptera, the postcubitus may be more closely associated with the vannal veins, but its base is always free from the latter. The postcubitus
12496-403: The head and inserted on the posterior lateral margins on two small sclerites, the tormae, and, at least in some insects, by a resilin spring in the cuticle at the junction of the labrum with the clypeus. Until recently, the labrum generally was considered to be associated with the first head segment. However, recent studies of the embryology, gene expression, and nerve supply to the labrum show it
12638-470: The head and mesothorax. Because the mesothorax and metathorax hold the wings, they have a combined name called the pterothorax (pteron = wing). The forewing, which goes by different names in different orders (e.g., the tegmina in Orthoptera and elytra in Coleoptera), arises between the mesonotum and the mesopleuron, and the hindwing articulates between the metanotum and metapleuron. The legs arise from
12780-453: The head are the occiput , postgena , occipital foramen , posterior tentorial pit , gula, postgenal bridge , hypostomal suture and bridge , and the mandibles , labium , and maxilla . The occipital suture is well-founded in species of Orthoptera, but not so much in other orders. Where found, the occipital suture is the arched, horseshoe-shaped groove on the back of the head ending at the posterior of each mandible. The postoccipital suture
12922-542: The head, thorax , and abdomen . The head is specialized for sensory input and food intake; the thorax, which is the anchor point for the legs and wings (if present), is specialized for locomotion; and the abdomen is for digestion , respiration , excretion , and reproduction. Although the general function of the three body regions is the same across all insect species, there are major differences in basic structure, with wings, legs, antennae , and mouthparts being variable from group to group. The insect's outer skeleton,
13064-469: The head, is the prothorax; its major features are the first pair of legs and the pronotum . The middle segment is the mesothorax; its major features are the second pair of legs and the anterior wings, if any. The third, the posterior , thoracic segment, abutting the abdomen, is the metathorax, which bears the third pair of legs and the posterior wings. Each segment is delineated by an intersegmental suture. Each segment has four basic regions. The dorsal surface
13206-523: The head, wing venation, and sometimes the last abdominal segment. The genitalia are very simple and do not provide clear species differentiation as in many other insect groups. In the past, most taxonomic treatments considered the family to be composed of three subfamilies: Pangoniinae (tribes Pangoniini, Philolichini, Scionini), Chrysopsinae (tribes Bouvieromyiini, Chrysopsini, Rhinomyzini), and Tabaninae (tribes Diachlorini, Haematopotini, Tabanini). Some treatments increased this to five subfamilies, adding
13348-524: The head. The mandibles are positioned between the labrum and maxillae . The mandibles cut and crush food, and may be used for defense; generally, they have an apical cutting edge, and the more basal molar area grinds the food. They can be extremely hard (around 3 on Mohs , or an indentation hardness of about 30 kg/mm ); thus, many termites and beetles have no physical difficulty in boring through foils made from such common metals as copper, lead, tin, and zinc. The cutting edges are typically strengthened by
13490-484: The hindwings of Acrididae are clearly the vannal regions, since their veins are all supported on the third axillary sclerites on the wing bases, though Martynov (1925) ascribes most of the fan areas in Acrididae to the jugal regions of the wings. The true jugum of the acridid wing is represented only by the small membrane (Ju) mesad of the last vannal vein. The jugum is more highly developed in some other Orthoptera, as in
13632-462: The labial palps have become modified to form the labellum, and the maxillary palps are present, although sometimes short. In Brachycera, the labellum is especially prominent and used for sponging liquid or semiliquid food. The labella are a complex structure consisting of many grooves, called pseudotracheae, which sop up liquids. Salivary secretions from the labella assist in dissolving and collecting food particles so they can be more easily taken up by
13774-457: The larvae are consumed by birds, as well as being paratised by tachinid flies , fungi, and nematodes . Adults are eaten by generalized predators such as birds, and some specialist predators, such as the horse guard wasp (a bembicinid wasp ), also preferentially attack horse-flies, catching them to provision their nests . Tabanids are known vectors for some blood-borne bacterial, viral, protozoan , and worm diseases of mammals, such as
13916-530: The larvae have a quiescent period during winter (diapause), while tropical species breed several times a year. In the majority of species, they are white, but in some, they are greenish or brownish, and they often have dark bands on each segment. A respiratory siphon at the hind end allows the larvae to obtain air when submerged in water. Larvae of nearly all species are carnivorous , often cannibalistic in captivity, and consume worms , insect larvae, and arthropods . The larvae may be parasitized by nematodes, flies of
14058-426: The larvae of Coleoptera and Hymenoptera. The larvae of Cyclorrhapha however, tend to have hardly any head capsule at all. The head capsule bears most of the sensory organs, including the antennae, ocelli, and compound eyes, along with the mouthparts. In the adult insect, the head capsule appears unsegmented, though embryological studies show it to consist of six segments that bear the paired head appendages, including
14200-486: The legs have two lobes on the sides (pulvilli) and a central lobe (empodium) in addition to two claws that enable them to grip to surfaces. Species recognition is based on details of head structures (antennae, frons , and maxillae ), wing venation, and body patterning; minute variations of surface structure cause subtle alterations of the overlying hairs, which alters the appearance of the body. Tabanid species range from medium-sized to very large, robust insects. Most have
14342-416: The long-spurred Madagascan star orchid Angraecum sesquipedale . The mouthparts of insects that feed on fluids are modified in various ways to form a tube through which liquid can be drawn into the mouth and usually another through which saliva passes. The muscles of the cibarium or pharynx are strongly developed to form a pump. In nonbiting flies, the mandibles are absent and other structures are reduced;
14484-492: The mandibles are modified to such an extent as to not serve any feeding function but are instead used to defend mating sites from other males. In ants , the mandibles also serve a defensive function (particularly in soldier castes). In bull ants , the mandibles are elongated and toothed, used as hunting (and defensive) appendages. Situated beneath the mandibles, paired maxillae manipulate food during mastication . Maxillae can have hairs and "teeth" along their inner margins. At
14626-432: The mesopleura and metapleura, as well as the mesosternum and metasternum. The tergal plates of the thorax are simple structures in apterygotes and many immature insects but are variously modified in winged adults. The pterothoracic nota each have two main divisions: the anterior, wing-bearing alinotum and the posterior, phragma-bearing postnotum. Phragmata (singular: phragma) are plate-like apodemes that extend inwards below
14768-413: The mesopleuron and metapleura. The mesothorax and metathorax each have a pleural suture (mesopleural and metapleural sutures) that runs from the wing base to the coxa of the leg. The sclerite anterior to the pleural suture is called the episternum (serially, the mesepisternum and metepisternum). The sclerite posterior to the suture is called the epimiron (serially, the mesepimiron and metepimiron). Spiracles,
14910-486: The mouthparts, each pair on a specific segment. Each such pair occupies one segment, though not all segments in modern insects bear any visible appendages. Of all the insect orders, Orthoptera displays the greatest variety of features found in the heads of insects, including the sutures and sclerites . Here, the vertex , or the apex (dorsal region), is situated between the compound eyes of insects with hypognathous and opisthognathous heads. In prognathous insects,
15052-428: The new instar to emerge from the integument. The frons is that part of the head capsule that lies ventrad or anteriad of the vertex. The frons varies in size relative to the insect, and in many species, the definition of its borders is arbitrary, even in some insect taxa that have well-defined head capsules. In most species, though, the frons is bordered at its anterior by the frontoclypeal or epistomal sulcus above
15194-420: The next segment. In mandibulate mouthparts, the labium is a quadrupedal structure, although it is formed from two fused secondary maxillae. It can be described as the floor of the mouth. With the maxillae, it assists with the manipulation of food during mastication or chewing or, in the unusual case of the dragonfly nymph , extends out to snatch prey back to the head, where the mandibles can eat it. The labium
15336-402: The outer margin, the galea is a cupped or scoop-like structure, which sits over the outer edge of the labium. They also have palps , which are used to sense the characteristics of potential foods. The maxillae occupy a lateral position, one on each side of the head behind the mandibles. The proximal part of the maxilla consists of a basal cardo, which has a single articulation with the head, and
15478-400: The performance of compound eyes. Because the individual lenses are so small, the effects of diffraction impose a limit on the possible resolution that can be obtained (assuming they do not function as phased arrays ). This can only be countered by increasing lens size and number. To see with a resolution comparable to our simple eyes, humans would require compound eyes that would each reach
15620-427: The preoral cavity, suspended from the clypeus in front of the mouth and forming the upper lip. On its inner side, it is membranous and may be produced into a median lobe, the epipharynx , bearing some sensilla . The labrum is raised away from the mandibles by two muscles arising in the head and inserted medially into the anterior margin of the labrum. It is closed against the mandibles in part by two muscles arising in
15762-488: The prick, the stab of gadfly-sting! O earth, earth, hide, the hollow shape—Argus—that evil thing—the hundred-eyed." William Shakespeare , inspired by Aeschylus, has Tom o' Bedlam in King Lear , "Whom the foul fiend hath led through fire and through flame, through ford and whirlpool, o'er bog and quagmire", driven mad by the constant pursuit. In Antony and Cleopatra , Shakespeare likens Cleopatra's hasty departure from
15904-451: The proboscis have evolved to give different species wider and therefore more advantageous diets. There is an allometric scaling relationship between the body mass of Lepidoptera and length of the proboscis from which an interesting adaptive departure is the unusually long-tongued hawk moth Xanthopan morganii praedicta . Charles Darwin predicted the existence and proboscis length of this moth before its discovery based on his knowledge of
16046-466: The proboscis, paired mandibles and maxillae. The maxillae form needle-like structures, called stylets , which are enclosed by the labium. When mosquito bites, maxillae penetrate the skin and anchor the mouthparts, thus allowing other parts to be inserted. The sheath-like labium slides back, and the remaining mouthparts pass through its tip and into the tissue. Then, through the hypopharynx, the mosquito injects saliva , which contains anticoagulants to stop
16188-433: The pseudotracheae or laid their egg on the suitable media; this is thought to occur by capillary action. The liquid food is then drawn up from the pseudotracheae through the food channel into the esophagus . The mouthparts of bees are of a chewing and lapping-sucking type. Lapping is a mode of feeding in which liquid or semiliquid food adhering to a protrusible organ, or "tongue", is transferred from substrate to mouth. In
16330-435: The pump. In Hemiptera and many Diptera, which feed on fluids within plants or animals, some components of the mouthparts are modified for piercing, and the elongated structures are called stylets. The combined tubular structures are referred to as the proboscis, although specialized terminology is used in some groups. In species of Lepidoptera, it consists of two tubes held together by hooks and separable for cleaning. Each tube
16472-454: The radial cross-vein (r) between R and the first fork of Rs, the sectorial cross-vein (s) between the two forks of R8, the median cross-vein (m-m) between M2 and M3, and the mediocubital cross-vein (m-cu) between the media and the cubitus. The veins of insect wings are characterized by a convex-concave placement, such as those seen in mayflies (i.e., concave is "down" and convex is "up"), which alternate regularly and by their branching; whenever
16614-428: The radius is flexibly united with the anterior end of the second axillary (2Ax). The fifth vein of the wing is the media. In the archetype pattern (A), the media forks into two main branches, a media anterior (MA), which divides into two distal branches (MA1, MA2), and a median sector, or media posterior (MP), which has four terminal branches (M1, M2, M3, M4). In most modern insects, the media anterior has been lost, and
16756-474: The salivary duct opens. It is commonly found fused to the libium. Most of the hypopharynx is membranous, but the adoral face is sclerotized distally, and proximally contains a pair of suspensory sclerites extending upwards to end in the lateral wall of the stomodeum. Muscles arising on the frons are inserted into these sclerites, which distally are hinged to a pair of lingual sclerites. These, in turn, have inserted into them antagonistic pairs of muscles arising on
16898-401: The same lead author shows that the stripes were no less attractive to tabanids, but they merely touched—and could not make a controlled landing to bite. This suggests that a function of the stripes was interfering with optic flow . This does not preclude the possible use of stripes for other purposes such as signaling or camouflage . Another disruptive mechanism may also be in play, however:
17040-453: The segments, and also bands of short setae (bristles). The posterior tip of each larva has a breathing siphon and a bulbous area known as Graber's organ. The outlines of the adult insect's head and wings are visible through the pupa , which has seven moveable abdominal segments, all except the front one of which bears a band of setae. The posterior end of the pupa bears a group of spine-like tubercles. Some species, such as deer flies and
17182-547: The site; other symptoms may include urticaria (a rash), dizziness, weakness, wheezing, and angioedema (a temporary itchy, pink or red swelling occurring around the eyes or lips). A few people experience an allergic reaction. The National Health Service of the United Kingdom recommends that the site of the bite should be washed and a cold compress applied. Scratching the wound should be avoided at all times and an antihistamine preparation can be applied. In most cases,
17324-435: The size of their heads. Compound eyes fall into two groups: apposition eyes, which form multiple inverted images, and superposition eyes, which form a single erect image. Compound eyes grow at their margins with the addition of new ommatidia. Antennae , sometimes called "feelers", are flexible appendages located on the insect's head which are used for sensing the environment. Insects can feel with their antennae because of
17466-425: The subcoxal segment of the ancestral insect leg. These sclerites may be separate, as in silverfish, or fused into an almost continuous sclerotic area, as in most winged insects. The pronotum of the prothorax may be simple in structure and small in comparison with the other nota, but in beetles, mantids, many bugs, and some Orthoptera, the pronotum is expanded, and in cockroaches, it forms a shield that covers part of
17608-468: The subfamily Adersiinae , with the single genus Adersia , and the subfamily Scepcidinae , with the two genera Braunsiomyia and Scepsis . A 2015 study by Morita et al. using nucleotide data , aimed to clarify the phylogeny of the Tabanidae and supports three subfamilies. The subfamilies Pangoniinae and Tabaninae were shown to be monophyletic . The tribes Philolichini, Chrysopsini, Rhinomyzini, and Haematopotini were found to be monophyletic, with
17750-468: The symptoms subside within a few hours, but if the wound becomes infected, medical advice should be sought. In Prometheus Bound , which is attributed to the Athenian tragic playwright Aeschylus , a gadfly sent by Zeus 's wife Hera pursues and torments his mistress Io , who has been transformed into a cow and is watched constantly by the hundred eyes of the herdsman Argus : "Io: Ah! Hah! Again
17892-505: The tentorium and labium. The various muscles serve to swing the hypopharynx forwards and back, and in the cockroach, two more muscles run across the hypopharynx and dilate the salivary orifice and expand the salivarium. Mouthparts can have multiple functions. Some insects combine piercing parts along with sponging ones which are then used to pierce through tissues of plants and animals. Female mosquitoes feed on blood ( hemophagous ) making them disease vectors. The mosquito mouthparts consist of
18034-561: The two lower halves of the postgena, are the hypostomal bridge, the postgenal bridge, and the gula. The hypostomal bridge is usually found in insects with hypognathous orientation. The postgenal bridge is found in the adults of species of higher Diptera and aculeate Hymenoptera , while the gula is found on some Coleoptera , Neuroptera , and Isoptera , which typically display prognathous-oriented mouthparts. Most insects have one pair of large, prominent compound eyes composed of units called ommatidia ( ommatidium , singular), up to 30,000 in
18176-409: The upper lip, and moves longitudinally. It is hinged to the clypeus. The mandibles (jaws) are a highly sclerotized pair of structures that move at right angles to the body, used for biting, chewing, and severing food. The maxillae are paired structures that can also move at right angles to the body and possess segmented palps. The labium (lower lip) is the fused structure that moves longitudinally and has
18318-542: The usual "media" is the four-branched media posterior with the common basal stem. In the Ephemerida, according to present interpretations of the wing venation, both branches of the media are retained, while in Odonata, the persisting media is the primitive anterior branch. The stem of the media is often united with the radius, but when it occurs as a distinct vein, its base is associated with the distal median plate (m') or
18460-419: The usual position anterior to the group of anal veins, the remigium contains the costal, subcostal, radial, medial, cubital, and postcubital veins. In the flexed wing, the remigium turns posteriorly on the flexible basal connection of the radius with the second axillary, and the base of the mediocubital field is folded medially on the axillary region along the plica basalis (bf) between the median plates (m, m') of
18602-445: The veins are convex, but each vein forks distally into an anterior convex branch and a posterior concave branch. Thus, the costa and subcosta are regarded as convex and concave branches of a primary first vein, Rs is the concave branch of the radius, posterior media is the concave branch of the media, Cu1 and Cu2 are respectively convex and concave, while the primitive postcubitus and the first vannal have each an anterior convex branch and
18744-404: The veins are formed where the two layers remain separate and the cuticle may be thicker and more heavily sclerotized. Within each of the major veins is a nerve and a trachea, and, since the cavities of the veins are connected with the hemocoel , hemolymph can flow into the wings. As the wing develops, the dorsal and ventral integumental layers become closely apposed over most of their area, forming
18886-410: The veins of the wing are subject to secondary forking and union by cross-veins. In some orders of insects, the cross-veins are so numerous, the whole venational pattern becomes a close network of branching veins and cross-veins. Ordinarily, however, a definite number of cross-veins having specific locations occurs. The more constant cross-veins are the humeral cross-vein (h) between the costa and subcosta,
19028-446: The venation may be reduced. In chalcidoid wasps , for instance, only the subcosta and part of the radius are present. Conversely, an increase in venation may occur by the branching of existing veins to produce accessory veins or by the development of additional, intercalary veins between the original ones, as in the wings of Orthoptera (grasshoppers and crickets). Large numbers of cross-veins are present in some insects, and they may form
19170-470: The vertex is not found between the compound eyes, but rather where the ocelli are normally found. This is because the primary axis of the head is rotated 90° to become parallel to the primary axis of the body. In some species, this region is modified and assumes a different name. The ecdysial suture is made of the coronal, frontal, and epicranial sutures plus the ecdysial and cleavage lines, which vary among different species of insects. The ecdysial suture
19312-623: The wide bodies of the insects and "dun-flies" to their sombre colouring. In Australia and the UK they are also known as March flies, a name used in other Anglophonic countries to refer to the non-bloodsucking Bibionidae . Adult tabanids are large flies with prominent compound eyes , short antennae composed of three segments, and wide bodies. In females, the eyes are widely separated; in males, however, they are almost touching. The eyes are often patterned and brightly coloured in living tabanids but appear dull in preserved specimens. The terminal segment of
19454-400: The wing base. The vannus is bordered by the vannal fold, which typically occurs between the postcubitus and the first vannal vein. In Orthoptera, it usually has this position. In the forewing of Blattidae, however, the only fold in this part of the wing lies immediately before the postcubitus. In Plecoptera, the vannal fold is posterior to the postcubitus, but proximally it crosses the base of
19596-526: The wing membrane. The remaining areas form channels, the future veins, in which the nerves and tracheae may occur. The cuticle surrounding the veins becomes thickened and more heavily sclerotized to provide strength and rigidity to the wing. Hairs of two types may occur on the wings: microtrichia, which are small and irregularly scattered, and macrotrichia, which are larger, socketed, and may be restricted to veins. The scales of Lepidoptera and Trichoptera are highly modified macrotrichia. In some minuscule insects,
19738-450: The world except for some islands and the polar regions (Hawaii, Greenland, Iceland ). Both horse-flies and botflies (Oestridae) are sometimes referred to as gadflies . Adult horse-flies feed on nectar and plant exudates ; males have weak mouthparts , but females have mouthparts strong enough to bite large animals. This is for the purpose of obtaining enough protein from blood to produce eggs . The mouthparts of females are formed into
19880-533: Was first recorded by Pliny the Younger and has survived as the generic name. In general, country folk did not distinguish between the various biting insects that irritated their cattle and called them all "gad-flies", from the word "gad" meaning "spike". Other common names include "cleg[g]", "gleg" or "clag", which come from Old Norse and may have originated from the Vikings . Other names such as "stouts" refer to
20022-470: Was mistaken by Comstock and Needham for the first anal. Proximally, the main stem of the cubitus is associated with the distal median plate (m') of the wing base. The postcubitus (Pcu) is the first anal of the Comstock and Needham system. The postcubitus, however, has the status of an independent wing vein and should be recognized as such. In nymphal wings, its trachea arises between the cubital trachea and
20164-683: Was the author of Die Fliegen ( The Flies ); he gave the name Haematopota , meaning "blood-drinker", to another common genus of horse-flies. Adult tabanids feed on nectar and plant exudates , and some are important pollinators of certain specialised flowers; several South African and Asian species in the Pangoniinae have spectacularly long probosces adapted for the extraction of nectar from flowers with long, narrow corolla tubes, such as Lapeirousia , and certain Pelargonium . Both males and females engage in nectar-feeding, but females of most species are anautogenous , meaning they require
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