AQUATIC INSECTS IN 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 piscicidium is br relly described by py 
in the paper just quoted. 
S. virgatum Ganmallett 
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 
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 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 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 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 8mm. In August; Las 
Vegas Hot Springs, N. M. 
S. vittatum Zetterstedt 
Ins. Lapponica. 1844. p.8038 
(= §. tribulatum Lugger) 
(According to Coquillett, decorum Walk. 1848 and argus Will. 1893 
are synonyms) 
Female. Gray; nearly bare; dorsum of thorax with five black 
stripes, the median one entire, the intermediate pairs inter- 
