274 INDIRECT BENEFITS DERIVED FROM INSECTS. 



flies, though their proboscis does not seem so well 

 adapted for animal as for vegetable food. 



The most unrelenting devourers of insects appear to 

 be those belonging to my fourth division, which attack 

 them under exery form. These begin the work of de- 

 struction when they are larvae, and continue it during 

 the whole of their existence. — The earwig that haunts 

 every close place in our gardens, and defiles whatever 

 it enters, probably in some degree makes up for its ra- 

 vages by diminishing the number of other insects. The 

 cowardly and cruel Mantis, which runs away from an 

 ant, will destroy in abundance helpless flies, using its 

 anterior tibiae, which with the thigh form a kind of for- 

 ceps, to seize its prey. The water-scorpions {Ncpa^ 

 Ranatra, and Naucoris)^ whose fore-legs are made like 

 those of the Mantis, the water-boatman (Notonecfa), 

 which always swims upon its back, and the Sigara, all 

 live by rapine, and prey upon aquatic insects. Some 

 of this tribe are so savage that they seem to love de- 

 struction for its own sake. One (Nepa cinerea) which 

 was put into a basin of water with several young tad- 

 poles, killed them all w ithout attempting to eat one. 



Those remarkable genera of the extensive tribe of 

 bugs {Chnicidce), which glide over the surface of every 

 pool with such rapidity, being gifted with the faculty 

 of walking upon the water, the Hijdrometra^ Vclia, and 

 Gerris of Latreille, subsist also upon aquatic insects. 

 A large number of the same tribe plunge their rostrum 

 into the larvae o^ Lepidoptera, and suck the contents of 

 their bodies ; and Reduvius personatus, which ought on 

 that account to be encouraged, is particularly fond of 

 the bed-bug. 



