Chaethippus mellinus (Becker), 1912a: 168

Riccardi, Paula Raile, 2020, Taxonomic revision of the genus Chaethippus Duda, 1930 (Diptera: Chloropidae) with the description of four species, Zootaxa 4802 (1), pp. 129-140 : 130-132

Chaethippus mellinus (Becker), 1912a: 168 ( Hippelates ).

( figs. 1–6 )

Type locality: Peru, Meshagua and Umahuanquiali, both on Rio Urubamba. Five syntypes at the Senckenberg Naturhistorische Sammlungen, Dresden, Germany.

Material examined. 2 ♂ and 20 ♀ from PERU, Madre de Dios, Tambopata Research Centr., 13.14°S 69.61°W, 23–25.vii.2001; Malaise trap 5; B. Brown & G. Kung leg. [ LACM and MZUSP] . 2 ♂ from PERU, Cuzco, 19 rd from Quincemil, rio Araza tributary; 13°20’10”S 70°50’57”W 874 m; 23–31.viii.2012; Malaise trap; R. R . Cav- ichioli, J.A. Rafael, A.P.M. Santos & D.M. Takiya leg. [ MZUSP] .

Diagnosis. Tibial spur well developed; two strong vibrissae; five to six prescutellar setae; anepisternum with or without a black spot; fore coxa with two long setae anteriorly, not spine-like.

Redescription. Body length, 2.8–3 mm. Wing length, 1.8–2 mm.

Head ( figs 1–2, 4 ). Wider than long dorsally and slightly higher than long in profile, entirely yellow except for black ocellar tubercle and a black spot on the ocellar triangle. Head and thoracic setae black. Frons slightly longer than wide, lateral margins subparallel, front margin very slightly concave. Ocellar triangle extending to three quarters length of frons, posterior margin three quarters width of frons, lateral margins straight, apex acute; macula blackish. Eye oval, long axis slightly oblique. Face wider than high; facial carina width as wide as aristal base, reaching the frontoclypeal suture; antenna yellow, postpedicel reniform, as high as long, blackened apically; arista entirely dark, with short pubescence, about 3 times as long as postpedicel; gena slightly narrower than length of postpedicel, covered with dark setulae; two strong vibrissae; occiput yellow, ventrally with a M-shaped black mark; proboscis short yellow, palpus yellow, equal in length to postpedicel, with dark setulae; labella with three pairs of pseudotracheae; clypeus yellow. Thorax ( figs. 1, 4 ). Scutum quadrate, yellow, slightly pruinose, with six orangish stripes and sparse dark setulae, a black mark on the anterior scutal concavity restricted to the area of insertion of the head; one posterior dorsocentral seta developed, longer than outer vertical seta; a row of five to six prescutellar setae; postpronotal lobe yellow with long seta equal to notopleurals; postalar seta developed, about as long as dorsocentral seta. Pleuron bare, yellow, a dark or orange spot on the anterior edge of anepisternum. Scutellum yellow pruinose, convex on the disc, with black setulae, wider than long, slightly triangular apically; apical scutellar setae with separation equal to that of posterior ocelli and longer than scutellum length; two pairs of lateral setae developed, as long as dorsocentrals; post-scutellum orange, shining. Wing ( fig. 3 ). Hyaline with brown veins covered in sparse brown microtrichia; costal sections 1–4: 9: 12: 6.5: 3.5; veins R 4+5 and M 1 almost parallel; distance between r-m and dm-m about five times length of r-m. Halter pale yellow. Legs ( figs. 1–2 ). Yellow, apical tarsomeres darkened; femoral organ with four rows of small spines; hind tibia with a long, curved preapical spur; posterior tibial organ short and oval, occupying less than half of tibia length, yellow. Abdomen ( fig. 1 ). As in the generic diagnosis. Male terminalia ( figs. 5–6 ). Remnant of the 6th sternite quadrate with the apex slightly arched. Epandrium wider than long, surstylus long, conical; cercus slightly long than wide, with one rounded lobe, with a very long seta. Hypandrium weakly sclerotized, closed; basiphallus cylindrical; distiphallus short, and membranous, striate; pre- and postgonite fused, finger-like, with sensory pores and a pair of small setae; phallapodemic sclerite rounded; phallapodeme short, not bifid apically; sperm pump present. Female terminalia. Segments 6–8 narrow; epiproct bare, with a pair of setae; hypoproct pilose; cerci light brown, long and narrow, with short setae.

Remarks. The syntypes of C. mellinus could not be examined. In the original description, there is a black spot on the anepisternum ( Becker 1912), while the specimens examined here possess a yellow spot on the anepisternum, which was considered here as an intraspecific variation. However, examination of the type series is desirable to confirm the identity of the examined material.

Figures

FIGURES 1–6. Chaethippus mellinus. 1, habitus (scale bar 1 mm). 2, head in frontal view (arrow points to the strong seta on the fore coxa). 3, wing. 4, head and thorax in dorsal view. 5, epandrium in terminal view. 6, male terminalia in ventral view (scale bar 0.1 mm). Abbreviations: bas, basiphallus; cer, cercus; dis, distiphallus; ep, epandrium; gon, gonites; hyp, hypandrium; phal, phallapodeme; phal s, phallapodemic sclerite; st 6, remnant of the 6th sternite.