INDIRECT BENEFITS DERIVED FROM INSECTS. 275 



of Erupts, whose haustellum resembles the beak of a bird, 

 carry off' in it Tipulariae and other small Diptera ; and 

 what is remarkable, you can seldom take these insects in 

 coitu, but the female has a gnat, some fly, or sometimes 

 beetle, in her mouth. Can this be to deposit her eggs 

 in, as soon as they are impregnated by the male ? or is 

 it designed for the nuptial feast? Even Scatophaga ster- 

 coraria and scybalaria, and probably many others of the 

 same tribe, feed upon small flies, though their proboscis 

 does not seem so well adapted for animal as for vege- 

 table food. 



The most unrelenting devourers of insects appear to 

 be those belonging to my fourth division, which attack 

 them under every 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 (Nepa, 

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

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

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

 by rapine, and prey upon aquatic insects. Some of this 

 tribe are so savage that they seem to love destruction for 

 its own sake. One (Nepa cinerea} which was put into a 

 basin of water with several young tadpoles, killed them 

 all without attempting to eat one. 



Those remarkable genera of the tribe of water-bugs 



T2 



