AQUATIC INSECTS IN NEW YORK STATE 371' 



S. pecuarum Riley 



U. S. Dep't Agric. Rep't for 188(5. 1887. p.512 (Coqnillett considers this a 



syuouym of S. 1 n v e u u s t u m Wallver) 



Plate 33, fig.G-11 



Female. Length 2.5mm to 4mm. Head uniform gra^ush slate,, 

 clothed with short yellowish hair, which becomes longer behind 

 the eyes; eyes black, with coppery or brassy reflections; an- 

 tennae black, with whitish pubescence, and with a few bristles- 

 on two basal joints, which are tinged with red, joints 1 to 11 

 gradually diminishing in thickness toward the last, joint 1 the 

 shortest, joints 2 and 3 twice as long as joint 1, joints 4, 5 and 

 G as long as joint 1, joints 7, 8, 9 and 10 gradually increasing 

 in length, last joint fusiform, twice as long as joint 10. Max- 

 illary palpi a little longer than the antennae, blackish, with 

 long graj'ish bristles. 



Thorax grayish slate, more or less densely covered with short,. 

 yellow hairs, and with usually very distinct markings, consist- 

 ing of two median dorsal, and two subdorsal broad, longitu- 

 dinal, sooty black bands, of which the latter curve to posterior 

 edge of patagium, which is reddish at tip; lateral edges of 

 prothorax with fine black sutures; underside of the thorax uni- 

 form grayish slate, with sparse yellow hairs, space around the 

 one large stigma lighter; halteres opaque, reddish white; legs^ 

 uniform reddish brown, densely covered with yellowish hairs; 

 tips of the tarsi blackish; wings subhyaline; larger veins and 

 base reddish brown. 



Abdomen nine jointed; joints subequal in length except the 

 last two, which decrease in length; a longitudinal, broad, bluish 

 gray dorsal band extends from near the base of second segment,. 

 where it is broadest, to the tip curving downward to the anterior 

 lateral edge of seventh segment; below this band laterally the- 

 color is blackish brown, with the exception of a broad bluish gray 

 transverse band on the posterior edge of each of the segments- 

 from 1 to 6; underside of abdomen uniform brownish gray, 

 without markings; abdomen densely covered with yellowish 

 hair, which is very long upon the posterior edge of segment 1^. 

 forming an overlapping fringe. 



Male. Length 1.5 to 2.2mm; differs considerably from the 

 female. Head not visible from above, being occupied by the very 

 large confluent eyes; the remaining parts below the eyes are 

 black, with black hairs and bristles; eyes composed of two differ- 

 ent kinds of facets, those above very large, twice as large as 

 those of female, and those in front and surrounding the 

 dwarfed trophi very minute, the dividing line between the sizes- 

 being abrupt; antenna similar to the female, more pro- 



