Calyxochaetus Bigot

Calyxochaetus Bigot Calyxochaetus Bigot 1888a: xxiv [1888b: xxiv]. Type species: Sympycnus nodatus Loew, by original designation [as “ Sympicnus notatus ”]. Note: Bigot (1888b) has often been cited as the first validation, but Bigot (1888a) was published a few months earlier (Evenhuis & Pont 2004). Nothosympycnus Wheeler 1899: 51. Type species: Nothosympycnus vegetus Wheeler, designated by Coquillett 1910: 576. Notosympycnus, error or unjustified emendation listed in Foote et al. (1965). Diagnosis. Males of Calyxochaetus, except C. angustipennis (Aldrich), C. longitarsus sp. nov. and C. tripilus (Van Duzee), can be recognized by having the scutellum bare except for one pair of large marginal setae (Fig. 5) and foreleg with short tarsomere 1 that is less than or equal to the length of tarsomere 2 (usually very short) (Figs 39–44, 82–86, 97, 98, 116–119). Females of all species, except C. angustipennis and C. tripilus (and perhaps C. longitarsus sp. nov. whose female is unknown), are distinguished from other sympycnines by the combination of having the scutellum bare except for one pair of large marginal setae (as in Fig. 5) and the proepimeron with one or more small white hairs (Fig. 6). Males and females of C. angustipennis, C. longitarsus sp. nov. and C. tripilus can be recognized by the combination of a scutellum bare except for one pair of large marginal setae and a glabrous, shiny frons (Fig. 18). About half of Calyxochaetus species have a glabrous, shiny frons which will further distinguish males and females from similar sympycnine genera (e.g., Erebomyia Runyon & Hurley, Parasyntormon, Neoparentia Robinson, and Sympycnus). The form of the aedeagus is a key synapomorphy shared by males of Calyxochaetus. In all species, the aedeagus (tubular, sclerotized) is separate from a broader aedeagal sheath (Figs 9–11). In other dolichopodids, the aedeagus and sheath are fused into a single structure, the phallus (Sinclair & Cumming 2006). The reversion to a separated aedeagus and sheath appears to involve only one sheath since the aedeagus remains enclosed by a second smaller sheath that sometimes separates subapically (Fig. 11). Redescription. Male. Wing length 1.9–3.6 mm. Head: Frons wide, partly to wholly brown pruinose, about half of the species with glabrous shiny blue-violet spot on either side of ocellar tubercle (Figs 6, 18). Ocellar tubercle brown pruinose with pair of strong divergent ocellar setae and pair of very small postocellar setae. Vertex with pair of strong proclinate vertical setae and pair of postvertical setae near vertex, slightly out of line with and usually slightly larger than postocular setae. Eyes with ommatrichia; ommatidia enlarged near face and clypeus. Face narrowed below, usually distinct to mouth (eyes contiguous in two species of fortunatus group); white, silver, gray, or brown pruinose; clypeus discernible, recessed, narrow, concolorous with face. Postocular setae in single row, white with uppermost few setae becoming pale brown to black. Antenna (Figs 15–17, 26–38, 77–81, 95, 96, 104– 115) dark brown to black, sometimes with scape and pedicel yellow-brown or partly yellow; scape usually laterally flattened and rather long, without setae; pedicel short, conical, with ring of black subapical setulae, never projecting thumb-like into postpedicel; postpedicel rather large, laterally flattened, usually ovate, never short triangular or sharply pointed, pubescent with microtrichia; arista-like stylus dorsobasal, black, usually (29 of 36 species) variously thickened and/or with apical lamella; article 1 rather long, usually extending to or beyond apex of postpedicel. Palpus small, oval, varying in color from white to black, usually paler apically, with small pale hairs and sometimes a few small brown to black setae. Proboscis small, brown to yellow-brown, with sparse brown hairs, each labellar lobe with 6 geminately sclerotized pseudotracheae. Thorax: Scutum and scutellum (Figs 1, 5) with thick brown pruinosity, often with weak green to blue-violet metallic reflections; scutellum sometimes with basomedial blue-violet reflections when viewed from above or behind (Fig. 5). Setae black. Mesoscutum flattened immediately anteriad of scutellum (flattened area subequal in size to scutellum). Pleura dark brown with gray pruinosity and often weak blue reflections, sometimes partly yellow. Proepisternum ventrally with 2 (rarely 3) small, white setae. Postpronotal lobe with 1 large seta and 0–2 small to very small setae. Proepimeron, anepimeron and metepimeron bare. Acrostichal setae uniseriate (often with anteriormost few pairs becoming irregularly biseriate). Setae arranged on each side with: 6 dorsocentrals, posteriormost dorsocentral pair widely separated; 3 intra-alar (seta at notopleural suture smallest); 2 supra-alar; 2 strong notopleural; 1 strong postalar; anterior scutum in front of dorsocentral, intra-alar and supra-alar rows with additional small setulae. Scutellum (Fig. 5) with posterior margin rounded, with 1 pair of strong marginal setae, without additional hairs. Legs: Mostly yellow, coxae and hind femora often partly brownish, tarsi becoming brown apically, hind tarsus usually mostly to wholly brown. Setae mostly black except those on fore coxa yellow, anterior surface of mid and hind coxae usually yellow, and specialized setae/hairs of femora, tibiae and tarsomeres often yellow or white. Tarsal claws, pulvilli and empodium very small and similar in size on all legs, never enlarged. Foreleg: Coxa mostly to wholly yellow (rarely fuscous), anterior surface with moderately dense yellow setae and about 6 larger yellow to yellow-brown setae along apical margin. Trochanter small, bare. Femur slender, usually wholly yellow (rarely brown basally), with weak posteroventral preapical seta. Tibia yellow, usually slender, sometimes swollen (Figs 82–86), without distinct setae, but sometimes with very small dorsal seta near 1/3, never with distinct anterodorsal row of small setae on distal half, apex with anterior comb-like row of close-set yellow setulae. Tarsus longer than tibia. Tarsomere 1 almost always very short and nearly round (as in Fig. 41), rarely short cylindrical (Figs 97, 98), longer than tarsomere 2 only in C. longitarsus sp. nov. and C. tripilus (Figs 20, 22). Tarsomeres 2–5 often modified with small setae and/or dorsal microsetulae, usually slender, rarely modified in shape. Midleg: Coxa with setae on distal half of anterior surface, with black (rarely yellow-brown) anterodorsal seta near 1/2.Trochanter small with small anterior seta.Femur slender,yellow,with distinct anterior and posteroventral preapical seta, sometimes with row of longer ventral setae. Tibia slender, yellow, with anterodorsal seta near 1/5 and 1/2, a posterodorsal seta from 1/5 to 1/3, sometimes with 1 to a row of several short posteroventral setae on distal half, with about 5 setae encircling apex, rarely with ventral row of specialized setae. Tarsus (Figs 21, 45–49, 87, 99–101, 120–131) modified in all species except C. longitarsus sp. nov. (Fig. 23), usually with at least a few longer anterior hairs or slender setae, tarsomeres 2–4 often modified in shape and width. Hindleg: Coxa with black (rarely yellow-brown) seta near 1/2 on outer surface, with 1 anteromedial seta at apex, otherwise bare. Trochanter with very small anterodorsal seta, small posterior seta, usually with 1–3 small ventral setulae at base. Femur broader than mid femur, mostly yellow and usually brownish apically, with distinct anterior preapical seta, sometimes with posterior preapical seta, with small anteroventral and posteroventral preapical seta, sometimes with specialized ventral setae (Figs 50, 51, 53). Tibia thicker than mid tibia, usually slightly enlarged apically, with anterodorsal seta between 1/5 and 1/3 and between 1/2 and 3/5, posterodorsally with row of slightly longer setae of varying lengths of which 3–6 equal to or longer than tibia width, ventrally usually with row of inconspicuous setae (less than width of tibia) that are sometimes slender and/or longer near base (Figs 132–136), with about 5 setae encircling apex. Tarsus unmodified, tarsomere 1 shorter than tarsomere 2 (subequal in C. pennarista), tarsomeres 2–5 decreasing in length apically. Wing (Figs 19, 56–63, 88–91, 137, 138): Hyaline or with slight brown tinge (sometimes only anteriorly), with brown veins, membrane covered with minute microtrichia. Anal lobe and area usually reduced, sometimes greatly so and wing appearing petiolate (Figs 57, 59, 61, 63). Posterior margin of wing sometimes with large lobe before, and excavated at, apex of M 4 (Figs 88, 89). Costa extending to M 1, with small setae, sometimes stronger basal to apex of R 1. Subcosta short, faint apically, fusing with R 1 near midpoint of R 1. R 1 short, fusing with costa in basal third of wing. R 2+3 long, ending in costa near 4/5 of wing length, nearly straight, sometimes curving slightly posteriorly near apex. R 4+5 usually weakly arched anteriorly, subparallel with M 1 apically. M 1 unbranched, nearly straight to slightly arching anteriorly beyond crossvein dm-m, with bosse alaire (slight flexion and wing indentation distal to crossvein dm-m). Membrane with weak to strong longitudinal crease running through crossvein dm-m. Crossvein dm-m placed near or just before middle of wing, half as long or less than distal section of M 4. Calypter yellow with apex narrowly brown or black (wholly yellow in C. angustipennis and C. tripilus), with fan of fine yellow setae. Halter yellow. Abdomen: Elongate cylindrical, with 6 exposed tergites, shiny dark brown usually with one or more of tergites 2–4 at least partly yellow (presence/absence and extent of yellow can vary within species), without obvious abdominal muscle plaques. Tergite 1 short, usually brown with some pruinosity, setae often black but sometimes partly white or yellow, those along posterior margin very long. Tergites 2–6 decreasing in length p