. Diptera Nematocera (excluding Chironomidæ and Culicidæ). Diptera. 158 BIBIONlDyi:, respects to that of the , among the Bkachyceba, but the very different venation and antennne, and the form of the anal cell (wider at the distal end than at the proximal) will at once indicate that they belong to the Nematocera. They are practically world-wide in their distribution, a good number of them being vernal or autumnal in their Fig. 16.—Bibio ohscuripemm, Meij.; a, antenna ; h, fore leg ; c, hind leg. Head genei'ally much flattened, in Bihio conspicuously so, some- times appearin
. Diptera Nematocera (excluding Chironomidæ and Culicidæ). Diptera. 158 BIBIONlDyi:, respects to that of the , among the Bkachyceba, but the very different venation and antennne, and the form of the anal cell (wider at the distal end than at the proximal) will at once indicate that they belong to the Nematocera. They are practically world-wide in their distribution, a good number of them being vernal or autumnal in their Fig. 16.—Bibio ohscuripemm, Meij.; a, antenna ; h, fore leg ; c, hind leg. Head genei'ally much flattened, in Bihio conspicuously so, some- times appearing more nearly horizontal than perpendicular. Eyes rounded or reniform, irrespective of sex; the upper facets in the male much larger than the lower ones, the two kinds sharply demarcated. Eyes in male very large, often occupying nearly the whole of the head ; contiguous or practically so ; in many species densely pubescent. In the female, the eyes are much smaller, wide apart, the trons sometimes being half the entire width of the head, sparsely hairy only, or bare. Three distinct ocelli present, closely contiguous in Bibio, in the shape of a triangle, the space on which they are placed, the " ocellar triangle,"' often much elevated above the level of the (contiguous) eyes (male), or frons (female). Proboscis short, blunt, with thick pubescent lamellae ; palpi variable, 4- or 5-jointed, long or short. Antennae of eight to twelve joints ; scape slightly but distinctly differen- tiated ; flagellum of rather closely applied bead-like joints, the last one conical. Thorax highly arched, generally closely pubescent. In Dilophus, armed on the dorsum with two peculiar transverse rows of strong teeth-like spines. Scutellum semicircular; metanotum fairly obvious. Abdomen a little longer than the body, of seven or eight seg- ments, broadly conical, sides sometimes nearly parallel. Genital organs of male consisting of a well-developed pair of two-jointed claspers, the 2nd joi
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectdiptera, bookyear1912
