Revision of the genus Calyxochaetus Bigot (Diptera: Dolichopodidae: Sympycninae) Author Runyon, Justin B. 0000-0002-0271-0511 Rocky Mountain Research Station, USDA Forest Service, 1648 S. 7 th Avenue, Bozeman, Montana 59717, USA justin.runyon@usda.gov text Zootaxa 2024 2024-11-21 5539 1 1 74 http://dx.doi.org/10.11646/zootaxa.5539.1.1 journal article 10.11646/zootaxa.5539.1.1 1175-5334 14240426 7BDB9666-CA90-40BF-8F65-B9897CDA1F2B Calyxochaetus lamellicornis Parent ( Figs 114 , 147 ) Calyxochaetus lamellicornis Parent, 1930: 105 . Type material examined. HOLOTYPE ♂ , labeled: “MUSEUM PARIS/ MEXIQUE / ÉTAT DE JALISCO / ENVIRONS DE GUADALAJARA / L. DIGUET 1914”; “NOVEMBRE”; “TYPE [red label]”; “MNHN, Paris/ ED11408” ( MNHN ) [photos examined]. Diagnosis. This Mexican species is distinguished from others in the frontalis species group by the weakly modified mid tarsus ( Parent 1930 , fig. 28; similar to Fig. 129 ) and arista-like stylus with elongate, narrowly oval apical lamella that is obliquely clipped at apex ( Fig. 114 ). Redescription (adapted from Parent 1930 ). Male. Body length 3 mm . Head: Frons shiny metallic violet. Face narrow, satiny white. Antenna ( Fig. 114 ) black; scape slightly shorter than postpedicel; postpedicel elongate oval, about 1.5X as long as wide; arista-like stylus with elongate, narrowly oval apical lamella, obliquely clipped across apex. Thorax: Metepimeron yellow. Scutellum with distinct blue-violet reflections. Legs: Foreleg : Yellow, tarsus dark brown from near apex of tarsomere 2. Tibia slender. Tarsomere 1 very short, about as long as wide. Tarsomere 3 subequal in length to tarsomere 4, with longer dorsal microsetulae at apex. Tarsomere 4 with longer dorsal microsetulae (some hooked) and row of slightly larger microsetulae across apex. Midleg : Yellow, except tarsomeres 2–5 black. Tarsus weakly modified ( Parent 1930 , fig. 28). Tarsomere 1 slightly longer than combined length of tarsomeres 2–5. Tarsomere 2 scarcely broadened apically, with small anteroapical projection bearing a few longer microsetulae. Tarsomeres 3–4 short, similar in size. Hindleg : Yellow, except tarsus black. Tarsomere 1 slightly but distinctly shorter than tarsomere 2. Wing: Tinged with brown; veins brown. Elongate oval and rather narrow, with anal area somewhat reduced. Abdomen: Tergites 2–3 mostly yellow except narrow median brown band. Tergite 4 with large yellow lateral spot. Female. Unknown. Distribution and seasonal occurrence. Known only from the type specimen from near Guadalajara, Mexico ( Fig. 147 ) collected in November. Remarks. Parent (1930) provided illustrations of the antenna, fore and mid tarsi, and wing. This species seems related to C. frontalis (whose males have an unmodified arista-like stylus) based on the similar, weakly modified mid tarsus. Although Parent (1930) did not note specialized ventral setae on the hind tibia of C. lamellicornis (and the hind tibia are now broken on the type ), I suspect such setae could be present and this species will run both ways in the key (couplet 27).