Callomyia browni Cumming, sp. nov.

Callomyia browni Cumming sp. nov.

(Figs 7, 18, 58, 66, 71)

Diagnosis. This southwestern Nearctic species is characterized by striking lemon yellow colour on the abdomen and halter, an expanded hind tarsomere 1 that is slightly broader than the apical width of the hind tibia, and male terminalia with a molar-like surstylus. Callomyia browni is most similar to the widespread Nearctic species C.

venusta, but can be distinguished by its lemon yellow markings on abdominal tergites 1–4 (versus yellow markings only on tergites 1–3, or even further reduced), yellow colour on sternite 8 (versus brownish-grey colour), strong stout posteroventral seta on the base of the hind femur (versus a somewhat longer and thinner posteroventral seta), broader hind tarsomere 1, two large very widely excavated surstylus cusps (versus less widely excavated), and a ventral inner surstylus cusp that is broadly truncate in posterior view (versus more narrowly truncate).

Description. Male (Figs 7, 18). Body length 4.1 mm; wing length 4.25 mm. Head brownish grey with silverblue reflections; face brownish-yellow ventrally; gena and postgena brown; mouthparts including palpus yellow; antenna with scape and pedicel brownish-yellow, first flagellomere and arista brown. Antenna with first flagellomere short-oval (as in Fig. 41).

Thorax black with silver-blue to silver-brown markings on postpronotal lobe, lateral portion of presutural scutum, notopleuron, postalar callus, propleuron, mesopleuron and metapleuron; posterior portion of postsutural scutum silver-blue; mediotergite and laterotergite silver-brown. Scutum with 6 notopleural setae.

Legs pale yellow with fore and mid tarsomeres 4 and 5 yellowish-brown, hind leg darker with apex of femur, tibia and tarsomeres brown. Mid tibia with median anterodorsal seta absent, median dorsal seta present (as in Fig. 50); base of hind femur with strong stout posteroventral seta (as in Fig. 53). Hind tarsomere 1 expanded, slightly broader than apical width of hind tibia, length approximately 2X width.

Wing hyaline with cell sc bluish-white. Halter lemon yellow with base of stem brown.

Abdomen with tergites 1–3 entirely lemon yellow; tergite 4 pale yellow, interrupted by median dorsal brown band extending posterolaterally; tergite 5 dark brown with anterolateral silver-blue marking; tergite 6 and 7 entirely dark brown; sternites white, sternite 8 pale yellow.

Terminalia (Figs 58, 66) with epandrium and hypandrium brown; surstylus dark brown; hypandrial process and cercus brownish-yellow. Epandrium with short broad ventral lobe, rounded at apex, slightly anteriorly directly; apical process moderately long, broad basally, pointed at apex. Surstylus molar-like, with 2 large cusps very widely excavated in between; dorsal outer cusp broadly rounded in lateral view; ventral inner cusp rounded in lateral view, broadly truncate and minutely serrate medially in posterior view (Fig. 66). Hypandrium with moderately long apical process; process trifid, with 2 minute apical projections and small basoventral lobe. Postgonite long and widened toward apex, somewhat truncated and pointed at apex. Phallus with sharp extended hook at apex. Cercus short.

Female. Unknown.

Type material. HOLOTYPE, ♂ labelled: “ USA: NM. Catron Co. 2.4km / W Luna. 7-8.VII.1987 / B.V.Brown.yellow pans/ 2300m.oak/ pine/ juniper; “ LACM ENT 304317; “ HOLOTYPE ♂/ Callomyia browni / H.J. Cumming [red label] [dissected] (LACM).

Geographical distribution and seasonal occurrence (Fig. 71). Callomyia browni is only known from the holotype collected in Catron County, New Mexico, in early July.

Etymology. This species is named after Dr. Brian V. Brown of the Natural History Museum of Los Angeles County, who collected the unique holotype.