AQUATIC INSECTS IN NEW YORK STATE SStJ 



a, number of them which were nearly ready to emerge were 

 •drawn from the pupal skins and examined for distinctive struo- 

 tural characters; but, excepting the difference in size, none were 

 observed. With freshly bred material, perhaps specific char- 

 acters might be obtained. 



The larvae of p i s c i c i d i u m is briefly described by Riley 

 in the paper just quoted. 



S. virgatum Coquillett 

 U. S. Nat. Mus. Proc. 1902. 25:97 



Male. Head and body black, antennae and mouth parts dark 

 brown, thorax gray pruinose, mesonotum marked with a narrow 

 median and laterally with a very broad velvet-black vitta 

 (viewed directly from above), mesonotum sparsely covered with 

 short, appressed hairs; abdomen on first six segments opaque, 

 velvet-black, a large silvery white spot on each side of the second 

 ^.nd sixth segments, venter near each side with an interrupted 

 jellow vitta on segments three to seven, composed of appressed 

 hairs, on each side of base of abdomen is a large cluster of yel- 

 low hairs, and a smaller cluster on each side of segments three 

 to five; femora and front tibiae yellow, their apices brown, 

 middle tibiae brown, a yellow ring beyond the base, hind tibiae 

 brown, the extreme base yellowish; tarsi black, broad base of 

 first joint and extreme base of the second on the middle and 

 hind tarsi light yellowish; wings hyaline, veins along the costa 

 yellowish brown, the others nearly hj^aline; halteres yellow. 



Female. Differs from the male as follows. Vittae of mesono- 

 tum brownish, the median vitta dilated posteriorly, wider than 

 •either of the lateral ones; viewed from in front the mesonotum 

 appears whitish pruinose and with two velvet-black vittae; 

 abdomen on the first five segments and sides of the sixth opaque, 

 gray pruinose, and with a velvet-black fascia at bases of three 

 to six, broadly interrupted on six, the middle of which and the 

 portion of the abdomen beyond it is very thinly pruinose and of 

 a dark brown color. Length nearly 3mm. In August; Las 

 Vegas Hot Springs, N. M. 



S. vittatum Zetterstedt 



Ins. Lapponica. 1&44. p. 803 



(= S. tribulatum Lugger) 



(According to Coquiliett, decorum "Walk. 1848 and a r g u s Will. 189.3 



are synonyms) 



Female. Gray; nearly bare; dorsum of thorax with five black 

 stripes, the median one entire, the intermediate pairs inter- 



