AQUATIC IX'SECTS IX NEW YORK STATE " 383 



a number of them which were nearly ready to emerge were 

 drawn from the pupal skins and examined for distinctive struc- 

 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. Pi-oc. 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 segTuents opaque, 

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

 and sixth segments, venter near each side with an interrupted 

 yellow 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 browq, 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 hyaline; 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 interrujtted 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. 1844. p.803 



(= S. t r i b u 1 a t u m Lugger) 



(According to Coquillett, decorum Walk. 1848 and a r g u s Will. 1893 



are synonyms) 



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

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



