SNOW-FLY. 231 
point, though some have been found when it was below zero 
and the surface of the snow was frozen into a solid crust. 
The long legs of the insect are very slender and it is difficult 
to understand why the blood circulating in them does not 
freeze solid when exposed to such low temperatures, especially 
as the flies moveso veryslowly. Intheillustration thelegs are 
not drawn in a natural position as this would require alto- 
gether too much space. Notwithstanding the cold it is love 
that brings the sexes together at this time and if a female 
has been discovered on the snow we usually find a male not 
far away. A few winters ago the writer discovered a female 
moving slowly over the snow and by searching he soon 
detected a male. Putting both together under an inverted 
glass the snow-flies immediately mated, notwithstanding it 
was several degrees below the freezing point. Soon after- 
ward the female found a crack in the glassy surface of the 
frozen snow, and forcing herself into it slowly disappeared 
from view. Penetrating to some depth into the snow she de- 
posited a number of elongated eggs, which, however, did not 
hatch. Most females found seemed to have the eggs already 
fully matured and only lacked to be fertilized. In desposit- 
ing their eggs the female inserts them into some crack by 
means of a large ovipositor, very large for the size of the in- 
sect. The male also possesses some remarkable features and 
especially two powerful claspers at the end of the abdomen. 
Both sexes are shown, as well as some of their peculiar 
anatomical features. 
