Conchopus Takagi, 1965 : 49

Masunaga, Kazuhiro & Saigusa, Toyohei, 2010, A revision of the Hawaiian and Wake Island species of the genus Conchopus Takagi (Diptera, Dolichopodidae), Zootaxa 2729, pp. 1-35 : 3

Conchopus Takagi, 1965: 49 .

(Type species: Conchopus rectus Takagi, 1965 , by original designation)

Diagnosis. The following diagnosis is for the rectus group. Small- to medium-sized dolichopodid flies (2.0– 5.5 mm). Body black in ground color, tinged with green. Mesonotum with inverted Y-shaped black marking on dense gray-white pollinose ground. Proboscis shorter than eye height. Conspicuous black and white markings on male mesoscutum. Thoracic pleura with setulae just in front of posterior spiracle. Wing venation not very modified in both sexes, middle section of vein M1+2 thickened in male except in C. acrosticalis , C. ciliatus sp. nov., and C. rectus . Fore femur with small subapical tubercle on ventral surface, and fore tarsomere 2 with some long anterodorsal setae in male.

Re-description. Head: Vertex not concave; occiput convex; ocellar tubercle distinct with 2 strong ocellar bristles and 2 minute postocellar setae. Frons with 2 strong frontal bristles. Face wider in females than in males. Face and clypeus divided by frontoclypeal suture. Face, clypeus, and palpus densely covered by grayish pollinosity in male. Apical epipharyngeal sclerite divided into two plates. Postocular ciliation black, erect, thick, and long. Gena absent. Palpus long, 2 times as long as wide, touching ventral margin of eye, and with many non-erect setae. Postgena with many long fine setae. Proboscis short, about 0.4–0.6 times as long as eye height. Eyes widely dichoptic, covered with minute white pubescence. Antenna: scape bare; pedicel with short setae subapically; 1st flagellomere tapered apically, 1.5–2.0 times as long as wide, with several short setulae; arista apical without any ornament. Thorax: Mesonotum with dense white pollinosity and mesoscutum marked with inverted Y-shaped, dull black pollinose marking with pair of long and narrow prongs in male; mesonotum somber in female. Thoracic bristles black. Chaetotaxy: acrostichals minute, biserial anteriorly and uniserial posteriorly, 6 dorsocentrals, several proepisternals, 1 each of humeral, posthumeral, prosutural, sutural, postsutural, supra-alar, and post-alar bristles, 2 (rarely 1) notopleurals. One to 5 setae in front of posterior spiracle. Scutellum with pair of strong inner marginal bristles and 2 short outer bristles (outer pair rarely absent). Mesopleurals usually present. Legs: Coxae concolorous with pleura; fore coxa with many setae on anterior apical margin; middle and hind coxae with prominent outer bristle. Male fore femur with small subapical tubercle on posteroventral surface. Fore tarsomere 1 much modified in male, with weak ventral tubercle bearing l–2 setulae between apical swelling and basal lobe. Fore tarsomere 2 with some long setae. Hind tibia with short apical process in male. Wing: None or very slight secondary sexual characters apparent in wing shape, venation, and markings, except M1+2 thickened in middle portion in males of some species. Abdomen: First tergum with long marginal setae. In male, sternum 4 with pair of strong bristles in center; sternum 5 with pair of strong, flat bristles on each posterior corner, and with pair of clusters of several spine-like bristles; and 6th sternum with midventral process posteriorly (called the pedunculate process in Takagi (1965)). In female, abdominal segments 6 and 7 telescoped, polished, and bearing pair of posterolateral setae on each tergum and sternum. Hypopygium oval, directed forward beneath tip of abdomen. Cercus elongate with many long setae, ventral lobe with several long setae at tip, hypandrium robust with bristle. Female terminalia with cercus strongly sclerotized; abdominal tergum 10 divided medially into 2 sclerites, each bearing 4 curved setae (acanthophorites); paraproct well developed and lobate, strongly sclerotized.

Distribution. Hawaiian Is., Japan, China, and Taiwan. There is an introduced species, Conchopus borealis Takagi , in North America ( Masunaga et al. 1999) and in South America ( Brooks & Cumming 2009).

Remarks. As discussed in the Introduction, Conchopus is herein restricted to the rectus -group of Conchopus Takagi s. lat. Conchopus s. str. is closely similar to the species of Conchopus exclusive of the rectus group in general appearance, but differs from them by the posterosubapical process of the male fore femur, the presence of setae on the thoracic pleura in front of the posterior spiracle, the lack of an auriform process on sternum 5, the short proboscis, the almost identical wing in both sexes, and the long setae on the fore tibia. The first character is considered to be the most prominent autapomorphy of this genus.