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 305799 10.11646/zootaxa.5539.1.1 fa176ed2-307a-4b37-a666-f1d25247f53b 1175-5334 14240426 7BDB9666-CA90-40BF-8F65-B9897CDA1F2B Calyxochaetus cilifemoratus species group Diagnosis. The C. cilifemoratus species group is defined by males having fore tarsomere 1 very short (as in Fig. 41 ) and mid tarsus slender with tarsomere 2 having the basal one-third to one-half slightly swollen (in dorsal or ventral view) and bearing 3–4 fine sinuous anterior setae (as in Figs 45, 47–49 ). Males also have the mid tarsomere 1 with 1–2 fine sinuous anterior setae at apex and mid tarsomere 4 usually with a fine sinuous anterior seta at apex. This group includes the only species of Calyxochaetus with a posterior preapical seta on the hind femur ( Fig. 54 , males and females). Females have a relatively wide face that is wider than postpedicel width. Scutellum without distinct blue-violet reflections. Remarks. Species in this group primarily occur in the shade of grasses, sedges, rushes and shrubs in otherwise open, moist habitats and I have collected specimens by sweeping the net close to ground between or through vegetation. The species of Calyxochaetus that occur at high elevations in western North America are found in this group.