. Bulletin - United States National Museum. Science. 28 TOUTED STATES NATIONAL MUSEUM BULLETIN 22 4. Text-Figure 8.—Pattern of distribution of the genus Dioctria Meigen. ment one is longer than the second; third segment, including microsegment, as long or longer than the hrst two segments combined and of approximately the same width. Third segment subcylindrical, slightly nar- rowed at the apex, and bearing a long, wide apically rounded, pubescent, spoon-shaped microsegment, which carries a distinct basal spine. First two segments with numerous, appressed, stiff, rather long bristles both on t
. Bulletin - United States National Museum. Science. 28 TOUTED STATES NATIONAL MUSEUM BULLETIN 22 4. Text-Figure 8.—Pattern of distribution of the genus Dioctria Meigen. ment one is longer than the second; third segment, including microsegment, as long or longer than the hrst two segments combined and of approximately the same width. Third segment subcylindrical, slightly nar- rowed at the apex, and bearing a long, wide apically rounded, pubescent, spoon-shaped microsegment, which carries a distinct basal spine. First two segments with numerous, appressed, stiff, rather long bristles both on the dorsal and ventrolateral surfaces; third segment with several appressed, dorsal bristles. In some species the first two segments may be nearly equal in length; in subgenus Eudioctria the antennae are still elongate, though all segments are reduced, including the third. Head, anterior aspect: Face between antennae one- fourth the head width and slightly divergent below; subepistomal area large, slightly oblique or rarely small and strongly oblique. Face micropubescent laterally and below, but often bare beneath the antenna and in the middle of the face; pile absent and bristles con- fined to a rounded cluster covering the lower facial eminence, containing more than 20 stout, curved bristles, or with only a single transverse row of 4 pairs. Front generally very short, polished and bare, in Eudioctria pollinose with a conspicuous row of rather long slender bristles along the ocular margin. Vertex moderately excavated; ocellar protuberance high with steep sides, and a few minute, short, anteriorly directed bristles confined to the posterior region, or in Eudioc- tria with 4 or 5 pairs of long, slender, central bristles. Eye facets at most slightly enlarged. Thorax: Low, gently curved, shining, often with pubescent vittae. Pleuron chiefly shining, with spots or diagonal bands of appressed pubescence. Pile of mesonotum rather scanty, erect and bristly; acrostical band present; d
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