TWO-WINGED INSECTS. 



297 



Fig. 230. 



They are generally most troublesome in warm climates, 

 and in the tropics they are present throughout the year. 

 But there are some cold countries in which, during their 

 brief but hot summers, they are not only extremely an- 

 noying, but occasionally very destructive. This is the 

 case with parts of Russia, both in Europe and in Asia. 

 Even such animals as horses, oxen, sheep, goats, and 

 hogs, are so severely stung by them as to die, some meet- 

 ing their death by drowning, having run into water to 

 escape the swarms of their small but formidable enemies. 

 At some periods it seems in that country to be the grand 

 business of life to devise and put in execution expedients 

 for guarding man and beast against these insects 



