258 INDIRECT BENEFITS DERIVED PROM INSECTS. 



awav a half-dead snake of about the size of a goose- 

 quill'. Some insects Avill even attack living animals 

 and make them their prey, thus contributing to keep 

 them within due limits. The common earth-worm is 

 attacked and devoured by a centipede {Scolopendra eke- 

 trica, L.). Mr. Sheppard saw one attack a worm ten 

 times its ovyn size, round which it twisted itself like a 

 serpent, and which it finally mastered and devoured. 



But insects are not only useful in removing and dis- 

 sipating dead animal matter, they are also intrusted 

 with a similar office with respect to the vegetable king- 

 dom. The interior of rotten trees is inhabited by the 

 larva; of Tipulce and other insects, which there find an 

 appropriate nutriment ; and a similar diet is fiirnished 

 to the grubs of the rose-beetle ( Cetonia mirata) by the 

 dead leaves and stalks usually to be found in an ant's 

 nest. Staph^linidce, SphcBridia^ and other Colcoptcra 

 are always found under heaps of putrescent vegetables ; 

 and an infinite number are to be met with in decom- 

 posing fungi, which seem to be a kind of substance in- 

 termediate between animal and vegetable. The Bo- 

 leti in particular have a genus of coleopterous insects 

 appropriated to them**, and the Lycoperdons another. 

 — Stagnant waters, which would otherwise exhale pu- 

 trid miasmata and be often the cause of fatal disorders, 

 are purified by the innumerable larvse of gnats. Ephe- 

 merae, and other insects which live in them and abstract 



* It is to be observed that in our cold climates, during the AviBter 

 months, wlien excrement and putrescent animal matter are not so oB"'?::!- 

 8ive, they are left to the action of the elements, insects being then torpid. 



'* Surely Mr. Marsham's name for this genus, Boletaria, is much more 

 proper than that of F.ibricius, Mycetopkagus (Agaric-eater), since these 

 insects seldom eat agarics. 



