23 spp. in 6 genera in our area(1)
, ~150 spp. in 15 genera total(2)
Slender-bodied without prominent hair. Usually black, but sometimes marked with yellow, or nearly all yellow (1)
. Facial orbits and cheeks not sutured (3)
. Calypters (lobes on base of wing along trailing edge) small or absent. Third antennal segment is elongated, execept in Rachicerus
, where the antennae appear to have many segments.
Vertex flush with eyes or slightly depressed, eyes widely separated in both sexes, antennal flagellum with an apical arista, or with 8 or 20-36 flagellomeres, pectinate, subpectinate, or serrate, clypeus recessed in a deep facial groove and flattened, in profile with anterior surface depressed below level of parafacial, and not reaching dorsally to bases of antennae
Scutellum usually unarmed, large, convex with a hairy disc, evenly rounded apically, subscutellum absent or very weakly developed; posterior thoracic spiracle never with a scale-like elevation immediately behind it
Legs slender, tibial spur formula 1-2-2, fore tibia with a ventral apical spur, precoxal bridge absent, empodia pulvilliform
Wings always present, C either extending to slightly beyond wing apex, or, as in most taxa, continued around the wing, branches of R and M diverging to apical wing margin, branches of M joining margin well below apex of wing, without a composite ‘diagonal vein’, branches of R not crowded anteriorly, Rs arising well before base of cell d, R2+3 ending at C near R1, R5 ending at or beyond wing apex, crossvein r-m close to base of cell d, cell d large, at least as close to posterior margin as to anterior margin of wing, at least 2 times as long as broad, M usually 3 branched, CuA, free or meeting A, in an acute angle near wing margin, anal lobe and alula well developed, calypters small
much of the world (none in the Afrotropical Region)(4)
; mostly northern NA(1)
Typically woodlands; larvae on decaying vegetation, under bark, or in decaying wood(1)
Adults sometimes take nectar and other fluids(1)
Larvae scavengers or predators(1)
larvae may prey on bark beetle larvae
Possibly sister to the Tabanomorpha.
Shin S, Bayless KM, Winterton SL, Dikow T, Lessard BD, Yeates DK, Wiegmann BM, Trautwein MD (2018) Taxon sampling to address an ancient rapid radiation: a supermatrix phylogeny of early brachyceran flies (Diptera). Systematic entomology, 43, 277–289. doi:10.1111/syen.12275.