GNATS, MIDGES, AND MOSQUITOES 229 



whatever else the insect may have in this way, it 

 does not use for sucking blood, being in fact perfectly 

 harmless. 



Gnats and mosquitoes are amongst that section of the 

 " thread-horned " flies whose early life is aquatic, and a 

 truly remarkable history is theirs. That creatures so 

 fragile should have at any time any connection with 

 so unstable and treacherous an element as water is 

 indeed strange, and unquestionably large numbers perish 

 through the mischances involved in this very associa- 

 tion. Nevertheless, so great is their fecundity that 

 the race runs no risk of extermination, notwithstanding 

 the dangers that beset the path of the individual in its 

 advance to maturity. The eggs are long oval objects, 

 and from the time of laying they are intrusted to the 

 water. The female, when about to lay, rests with her 

 first pair of legs on some floating stick or leaf, or other 

 support, the second pair gently touching the water, 

 while the third project over its surface. Crossing these 

 like an X, she allows an egg to pass into the angle 

 where they meet ; this is soon followed by another and 

 another, their moist and glutinous surfaces causing 

 them to adhere to one another with the long axis nearly 

 perpendicular. In this way a collection of some 200 or 

 300 is built up into the form of a tiny raft, concave 

 above a sort of miniature lifeboat, so constructed that 

 no capsizing can take place. The egg-raft once made, 

 the maternal duties are over, and the little craft drifts 

 rudderless away, exposed to sun and storm. This 

 venturesome voyage, however, lasts but a few days ; 

 and then, the eggs having been from the first placed 

 upside down in the water, the lower end of the shell is 

 forced off, and the newly hatched grub finds itself at 



