58 Insect Life : Its Why and Wherefore 
the myriads of these larvae and pupae as 
gnats going through their various stages 
of existence and also take into consideration 
what a very short space of time is occupied 
in the process, many, many generations 
of gnats are produced and perfected in 
the course of the year. We probably have 
to thank the swallow and other birds for 
reducing the numbers very considerably, or 
gnats at their ordinary rate of increase would 
make life something other than pleasurable 
during the summer months. Like many 
another insect it is very susceptible to 
climatic changes, sometimes flying high, 
sometimes almost skimming the ground. It 
is frequently observed that they are more 
virulent in their attacks on man when 
there is considerable atmospheric dis- 
turbance. The emptying of all unnecessary 
vessels of water and the draining of pools 
will help to rid a locality to a great extent 
of gnats. For though ubiquitous in its 
haunts, geographically speaking, the insect 
has special localities where it teems in 
greater quantities, these generally being 
in close proxmity to a suitable breeding 
place. In reading these remarks, many will 
