As in all insects, the abdomen of a fly is primitively composed of 11 segments. The terminal portion, consisting of the rudiments of segment 11, namely a pair of cerci and the anus, is called the proctiger. There is no evidence of a 12th segment.
The basal segments of the abdomen (preabdomen), consisting of segments 1-5 or 1-6, are frequently broader than the terminal portion of the abdomen, referred to as the terminalia (postabdomen, hypopygium). Basically each abdominal segment consists of a dorsal tergite and a ventral sternite connected laterally by the pleural membrane. Of special interest are one or more pairs of sensory setulae (alphasetae, sensilla trichodia) that are frequently present on the anterior margin of the sternites (ex McAlpine 1981).
Virtually all Diptera have five tarsomeres (tarsal segments) on all legs. They are called the first (basitarsus, metatarsus, proximal tarsal segment), second, third, fourth, and fifth tarsomeres (ex McAlpine 1981).
Segment of leg between trochanter and tibia (ex McAlpine 1981).
Explanation:
The femora and tibiae are usually about the same length and are almost always the longest of the leg segments. Both are extremely long and slender in many Tipulomorpha, but the femora are usually stouter than the tibiae. The fore femur is particularly strongly developed in forms with raptorial forelegs, e.g. some Ceratopogonidae, certain Empididae, and a few Ephydridae. All femora may be armed with specialized spines, tubercles, or processes, especially on the ventral surfaces. In many groups the distal end of the anteroventral surface of the fore femur bears a comb-like row of spinules called a ctenidium. A crest-like, sound-procudings scraper occurs on the posterior surface of the hind femur as part of a stridulation mechanism in certain Agromyzidae and Chamaemyiidae (ex McAlpine 1981).
All coxae articulate dorsally with a coxifer or pleural process at the ventral end of the pleural suture of each thoracic segment. Ventrally the fore coxa articulates with the side of the exposed prosternum. The mid and hind coxae adjoin their corresponding invaginated furcasterna. Usually all coxae are short and stout, but in some forms with raptoral legs, e.g. certain Empididae, the fore coxa is as long as or longer than the femur and relatively slender. In the Mycetophilidae all coxae are rather long (ex McAlpine 1981).
Each leg consists of a coxa, trochanter, femur, tibia and tarsus. The structure of these segments differs in the fore leg, mid leg, and hind leg (pro- meso-, and meta-thoracic legs), and all legs sometimes show striking modifications on all segments. The different leg surfaces are ascertained by imagining that all the legs are fully extended laterally, parallel to each other and at right angles to the main axis of the body. Thus each segment of each leg has an anterior, posterior, dorsal, and ventral surface. Other surfaces are named on the same basis, e.g. anterodorsal and posteroventral (ex McAlpine 1981).
The posterior cubital cell (cell cup) is formed by CuA2, A1 and CuP (ex McAlpine 1981).
Explanation:
The size and shape of this cell is governed by the position of CuA2, which ends on A1 instead of reaching the wing margin, and it provides many useful taxonomic characters (ex McAlpine 1981).
Wing vein between radius and cubitus (ex McAlpine 1981).
Explanation:
The anterior branch of the media is extremely reduced and never reaches the wing margin in Diptera. The components of the posterior branch are called M1, M2, and M3 (ex McAlpine 1981)
Scratchpads developed and conceived by (alphabetical):
Ed Baker,
Katherine Bouton
Alice Heaton
Dimitris Koureas,
Laurence Livermore,
Dave Roberts,
Simon Rycroft,
Ben Scott,
Vince Smith
