138 PISCATORIAL ENTOMOLOGY. 



powers with which they are invested. When myriads of 

 flies are observed depositing their eggs literally by 

 millions, upon water or land, we are led to investigate 

 the reason why their material increase is seldom 

 rendered notable, and we find that the mass simply 

 go to feed other creatures, whose sole mission would 

 appear to be to counteract, regulate, and hold in check 

 their kindred species. All insects of the smaller kind, 

 inhabiting the earth or water, feed upon the ova of 

 the different orders of winged insects, the pupae of 

 which retaliate in turn by preying continuously upon 

 the minute insects, the enemies of their previous 

 existence. Thus, by a wondrous scheme of Providence, 

 the perfect chain of animated nature and organised 

 creation is accurately preserved. 



When insects arrive at maturity, there is this signal 

 and distinctive difference between the aerial and 

 aquatic species. The former are voracious feeders 

 when in their perfect state ; the latter do not, as we 

 have shown, feed at all when in the subimago and 

 perfect stages of their existence, so that no devastat- 

 ing results issue from any multiplication of these. The 

 same observation cannot be applied with equal truth 

 to the case of the land insects, which, when plentiful, 

 are the bane of man and beast. Reaumur makes 

 mention of a swarm of May flies or drakes on the 

 Marne, which completely covered him two or three 

 inches in depth, in the space of a few minutes. Most 

 fishermen have experienced something similar, at 

 long intervals, with regard to the water flies in certain 

 localities : this is the result of a combination of 



