THE THICK-LEGGED SNOW-GNAT. 
601 
along, it seems almost to tread the air, balancing itself hori- 
zontally with its long legs, which are stretched out, like rays, 
from the sides of its body. 
There are exceptions to almost all general rules. Thus we 
find, among Dipterous insects, some kinds that never have 
wings. One of these is the thick-legged snow- 
gnat, or Chionea valga 1 (Fig. 260). This singu- 
lar insect looks more like a spider than a gnat. 
Its body is rather less than one fourth of an inch 
long, and is of a brownish yellow or nankin color. 
The legs are rather paler, and are covered with 
short hairs. The head is small and hairy. The first two 
joints of the antennae are thick, the others slender and 
tapering, and beset with hairs. Although the wings are 
wanting, there is a pale yellow poiser on each side of the 
hinder part of the thorax. The hindmost thighs are very 
thick, and somewhat bowed, in the males, which suo-o-ested 
the name of valga , or bow-legged, given to the insect in my 
Catalogue. The body of the female ends with a sword- 
shaped borer, resembling that of a grasshopper. These 
wingless gnats live on the ground, and the females bore 
into it to lay their eggs. They are not common here. Mr. 
Gosse found considerable numbers of them in Canada, 
crawling on the snow, in pine woods, during the month 
of March.* 
Travellers and new settlors, in some parts of New Eng- 
land and Canada, are very much molested by a small gnat, 
called the black fly ( Simulium molest uni), swarms of which 
fill the air during the month of June. Every bite that they 
make draws blood, and is followed by an inflammation and 
[ 1 Mr. Walker has described two American species of this singular genus; one 
of them, Chionea aspera, seems to be identical with Dr. Harris’s C. valya. I do 
not undertake to decide which name should be preferred. Dr. Harris’s has the 
priority, but the few words ho mentions about this insect can hardly bo called a 
description. (Compare Walker's List of Diptera of British Museum, Vol. I. p. 82.) 
— Osten Sacken.] 
* Canadian Naturalist, p. 51. 
7G 
Fig. 260. 
