SIMULIUM. 183 



male, the upper facets very much larger than the lower ones, and 

 sharply demarcated from them ; in the female the eyes separated 

 by a moderately broad, nearly linear frons, flat, about one-fourth 

 or one-third the width of the head, all the facets of equal size. 

 Proboscis moderately produced, perpendicular, conical, with two 

 horny labella of moderate size towards the tip. Palpi four-jointed, 

 elongate, cylindrical, incurved; 1st joint short, the following 

 three subequal, or the 4th the longest. Palpi rather longer in the 

 female than in the male. Antennaa short, robust, ten-jointed,* 

 the two scapal joints differentiated, short, the flagellar joints 

 rather thickly annular, subequal in length, the last one sub-conical, 

 all somewhat compressed; with short thick pubescence, no bristles 

 present. Thorax ovate, short, highly arched and robust, almost 

 gibbose, bare or with sparse hair. Scutellurn small, metanotum 

 not conspicuous. Abdomen broad, short, hardly longer than the 

 thorax, very shortly pubescent, of seven or eight segments, the 

 first being distinctly the longest, projecting somewhat over the 

 base of the second, and with a peculiar elevated ridge at the base 

 running across from side to side. The 1st segment also has a 

 more or less fan-shaped row of long hairs on each side towards 

 the lateral margin, which gives the appearance at first sight of 

 large tegulae with a conspicuous fringe. Genitalia inconspicuous 

 in both sexes. Legs quite short and stout, in contradistinction to 

 the usual nematocerous type. Fore coxae and four trochanters 

 comparatively large ; femora flattened, somewhat broad ; tibiae 

 normal, without apical spurs ; metatarsus greatly developed, 

 nearly as long as the rest of the tarsus, the four remaining joints 

 short, especially the last ; empodia and pulvilli rudimentary. The 

 metatarsus is generally dilated to a greater extent in the male, in 

 which sex the legs are usually rather more pubescent than in the 

 female. The 1st and 3rd tarsal joints generally bear two long 

 hairs each, the character appearing to be common to many 

 species. Wings very large and broad, comparatively short, incum- 

 bent, bare ; costal vein ending at about tip of 3rd longitudinal 

 vein ; auxiliary vein and 1st longitudinal ending in the costa ; 

 2nd longitudinal absent ; 3rd springing from the middle of the 1st 

 and ending in the costa much before the wing-tip, humeral cross- 

 vein present; subcostal cross-vein absent; anterior cross-vein 

 present, uniting the 3rd vein, near its base, to the 4th vein just 

 before it forks. The above veins, including the costa and the 

 basal part of the 4th longitudinal (i. ., up to the anterior cross- 

 vein) strongly developed and somewhat approximate to one 

 another. The remaining veins very faint. The 4th vein forked,, 

 the oth, 6th, and 7th veins simple, the 6th being strongly In- 

 sinuate ; all these veins attaining the border of the wing or very 

 nearly so. Some spurious veins or " folds '*' of the wings appear 

 as additional veins, and must not be confused with the real veins 



* Zetterstedt is in error in describing the antennae as eleven-jointed. 



