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 move so very slowly. In the illustration the legs 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 sno^w, and forcing herself into it slowly disappeared 

 from view. Penetrating to some depth into the snow she de- 

 posited a number of elongated eggs, w^hich, 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. 



