|
The Phoridae are a family of small, hump-backed flies resembling fruit flies. Phorid flies can often be identified by their escape habit of running rapidly across a surface rather than taking to the wing. This behaviour is a source of one of their alternate names, scuttle fly. Another vernacular name, coffin fly, refers to ''Conicera tibialis''.〔Colyer, C.N. (1954) The 'coffin fly', ''Conicera tibialis'' Schmitz (Dipt., Phoridae). Journal of the Society for British Entomology, 4, 203-206.〕 About 4,000 species are known in 230 genera. The most well-known species is cosmopolitan ''Megaselia scalaris''. At 0.4 mm in length, the world's smallest fly is the phorid ''Euryplatea nanaknihali''.〔Brown, B.V. 2012: Small size no protection for acrobat ants: world's smallest fly is a parasitic phorid (Diptera: Phoridae). ''Annals of the Entomological Society of America'', 105(4): 550-554. 〕 == Description == For terms see Morphology of Diptera Phorid flies are minute or small - 0.5–6 mm (– in) in length. When viewed from the side, a pronounced hump to the thorax is seen. Their colours range from usually black or brown to more rarely yellow, orange, pale grey, and pale white. The head is usually rounded and in some species narrowed towards the vertex. The vertex is flat. In some species, the ocellar callus is swollen and highly raised above the surface of the vertex. The eyes are dichoptic in both males and females (eyes of males close-set, of females wide-set). The third segment of the antenna is large and rounded or elongated, and bears a long apical or dorsal arista directed sideways. The arista is glabrous or feathered. The third antennal segment in some species is unique in shape. Sexual dimorphism is often shown in the shape and size of third segment of antennae, and in males, the antennae are usually longer. The proboscis is usually short and sometimes with enlarged labella. The proboscis may be elongated, highly sclerotized, and bent at an angle. Maxillary palpi vary in shape and are sometimes large (species of genus ''Triphleba''). The groups of bristles are developed on the head. Two pairs of supra-antenna1 bristles, sometimes one , are completely reduced. Above these are antenna1 bristles closer to (but still some distance from) the margin of eyes. Three bristles are spaced along the margin of eyes-anterolateral midlateral and posterolateral. Immediately before the ocellar callus are two preocellar bristles. The ocellar callus bears a pair of ocellar bristles and in some genera between the antennae and the preocellar bristles two additional, intermediate bristles occur. The convex mesonotum is usually covered with hairs and rows of bristles. An important taxonomic character is the precise location of the anterior spiracles on the pleura of the thorax. The metapleuron may be entire or divided by a suture into two halves, and either with a few long bristles glabrous, or pubescent. The legs have stout femora and the hind femora are often laterally compressed. The wings are clear or tinged only rarely with markings. They have a characteristic reduced wing venation. The strong, well developed radial (R) veins end in the costa about halfway along the wing. The other veins (branches of the medius) are weaker and usually follow a diagonal course and are often parallel to each other. Crossveins are totally absent. The costa reaches only to the point of confluence of alar margins with veins R4+5 or R5. The ratio of first, second, and third sections of the costa is often a reliable specific character. Other costal indices (compared to other wing measurements) are used in the taxonomy. Two rows of well developed bristles are present on the costa and almost at a right angle to each other. The subcosta is reduced. Of the radial veins, only R1 and R4+5 are developed. R4+5 may furcate at end. R4 and R5 may merge into the alar margin separately or continue as a single vein to the end. Medial veins are represented by M1, M2, and M4. The anal vein may reach the alar margin, or is greatly shortened or almost atrophied. The abdomen consists of six visible segments. Segments VII to X comprise the genitalia of the male (hypopygium), and in the female the terminalia. In some genera, segments VII to X in the female are highly sclerotized and extended into a tube ("ovipositor"). Segments VII and VIII of the male are more or less sclerotized in the genus ''Megaselia'', but otherwise mostly membranous. Tergite 9 the (epandrium) is highly developed and usually fused at least on one side with the hypandrium (sternite 9). Only in the genus ''Megaselia'' is the hypandrium more or less distinctly separated from the epandrium. Unpaired sclerites (ventrites) developed at the distal end of the hypandrium vary in shape. They may be flat, swollen, or other. Sclerites are always present near the base of the cerci, which may be highly developed, and converted either into a tube (anal tube) or a pair of asymmetrical large outgrowths (''Phora''). The phallosome is rarely complex in structure. The larva is small, rarely over 10.0 mm long and typically has 12 visible segments. The shape varies from fusiform with inconspicuous projections on posterior segments to short, broad, and flattened with conspicuous dorsal and lateral plumose projections especially on the terminal segment. The colour is whitish, yellowish white, or grey. The first instar is metapneustic, later instars are amphipneustic. Pupation occurs in the last larval skin which hardens and becomes reddish. The puparium is oval, pointed at ends (because the larval extremities remain relatively unchanged). Abdominal segment 2 has a dorsal pair of long, slender pupal respiratory horns. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Phoridae」の詳細全文を読む スポンサード リンク
|