Oedematopus Van Duzee, 1929

Naglis, Stefan M., 2011, Revision of the genus Oedematopus (Diptera, Dolichopodidae) with the description of a new genus and a key to the Neotropical genera of Hydrophorinae, Zootaxa 2756, pp. 40-52 : 42-43

Genus Oedematopus Van Duzee, 1929

Type species: Oedematopus crassitibia Van Duzee, 1929 (by monotypy).

Diagnosis. Mesonotum with silvery white pruinosity along area of dc rows; ac absent; 6 pairs dc decreasing in size anteriad, sometimes small and posterior most seta sometimes hair-like; 2 strong scutellar setae; first flagellomere ovate, arista dorsal; cross-vein dm-cu parallel to posterior wing margin; hypopygium partially hidden under postabdomen; male genitalia: surstylus divided into dorsal and ventral lobes, postgonite present.

Description (male). Head: Face broad, almost parallel; eyes hairy; fronto-clypeal suture distinct, clypeus slightly protruding; “cheeks” not present; palpus long, narrow and apically pointed, with long hairs; antenna dark; scape longer than pedicel and bare; pedicel short, with circlet of small apical setae; first flagellomere ovate, about as long as wide; arista dorsal and bare; frons broad, frons and vertex with dense dark pruinosity and sometimes with silvery white maculation ( crassitibia ); pair of ocellar setae present, vertical setae and postvertical setae absent; upper postocular setae black and uniseriate, lower setae pale and mulitseriate; proboscis distinct and dark. Thorax: Scutum with dark dense pruinosity and with silvery white maculation along area of dc rows; ac absent; 6 pairs of dc decreasing in size anteriad and posterior most sometimes hair-like ( crassitibia ); 2 strong scutellar setae, and sometimes with small median setae ( vidua ); 1 hm, 0 pm, 1-2 np, 1 small sr, 1 sa, 1 pa; lower propleuron sometimes with 1 strong pale seta ( vidua ) and upper with pale hairs. Legs: All legs dark; CI with pale hairs, CII and CIII bare; FI slightly thickened at base, femora often with long hairs or special setation (MSSC); TIII strongly swollen in crassitibia and maroviensis; pulvilli absent, claws very well developed. Wing: Hyaline, sometimes with brown infuscation; R4+5 bent posteriad before wing margin; distal section of M parallel to posterior wing margin; cross-vein dm-cu almost parallel to posterior wing margin and about 5 times as long as distal section of CuA. Abdomen: Stout and thick, about as long as thorax, dorsoventrally flattened basally; sternum 4 forming hood and partially enclosing hypopygium; cercus broad, visible under post abdomen; epandrial lobe narrow; surstylus divided into dorsal and ventral lobes; postgonite present. Female: Similar to male, but face broader and abdomen more flattened dorsoventrally.

Remarks. Van Duzee (1929, 1930) mentioned in his description of the genus that dc are absent or reduced to small hairs anterior to the suture, and Becker (1922) also mentions: “without visible rows of dorsocentral and acrostichal setae”. But examination of types and other material of both species, O. crassitibia and O. vidua , revealed that 6 pairs of dc are present in males and females at the usual positions even if they are relatively small.

The wing illustration in Bickel (2009, fig. 48) is that of Oedematopiella .