1847.] Winter Insects of Eastern New York. y 
reaching but half the length of the wings; sutures of the tergum 
in the female more or less widely marked with dull rufous; tip, in 
the female only, furnished with two short, filiform sete, scarcely 
equalling in length the segment to which they are attached; sete 
pale lurid, sub-diaphanous, hairy, composed of about eight joints. 
Each segment of the venter with two transverse impressions, one 
situated towards each posterior angle. Male organ exserted, 
forming a conical lurid point near the base of the last ventral 
‘segment.. Femurs cylindrical, black, clothed with white hairs, 
which are longer and more distinct in the females, inner side with 
a narrow deep groove which is dilated towards the apex. Tibia 
cylindrical, about half the diameter of the femurs, grooved, lurid- 
brown, diaphanous, the ends and inner sides black; apex slightly 
incurved and armed with two short spines on the inside. Tarst 
black, composed of three joints, whereof the middle one is slight- 
ly shorter; two claws and an intervening pellet at the tips. 
Wings griseous, when closed showing faintly two paler bands, 
one near the middle and the other back of it; edges ciliated with 
fine, short hairs. Upper wings diaphanous, grey, faintly marked 
with a darker cloud back of the middle, and another occupying 
the tips, but not reaching to the edge, these clouds becoming 
wholly obliterated in cabinet specimens; nervures black. Lower 
wings grey, sub-hyaline, nervures black. 
When recently excluded from the pupa, the abdomen, except 
at its tip, is ofa dull rufous color; this gradually becomes darker, 
and finally pure black. For a time after the venter has become 
wholly black the tergum continues dull rufous with a black band 
on each segment, which band does not reach the lateral margins. 
These bands increase in size, and at length the whole tergum is 
overspread with pure black. 
Tt is not uncommon to meet with specimens of this and the pre- 
ceding species, infested with a minute parasite of the family Aca- 
ride. These parasites are of a bright vermillion-red color, and 
fix themselves, one or more,-at the sutures of the tergum, not 
quitting their hold after the death of the insect, unless disturbed. 
This species begins to appear, soon after the Small Snow-fly is 
first met with. It occurs in the same situations, is nearly as 
abundant, and remains for a time after that has disappeared. One 
of the purposes served by these prolific insects in the economy of 
nature, doubtless is, to supply with food the fish of our streams, 
at this early period of the year. The larger of these species, con- 
tinuing to be abundant when the the shad first come into our riv- 
ers, has evidently received one of its popular designations in al- 
lusion to this fact. 
We regard this as the American analogue of the European - 
Nemoura nebulosa, Linn. But, from several points in the extend- 
