256 INDIRECT BENEFITS DERIVED FROM INSECTS. 



them within due limits. The common earth-worm is at- 

 tacked and devoured by a centipede (Scolopendra elec- 

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

 times its own size, round which it twisted itself like a ser- 

 pent, and which it finally mastered and devoured. 



But insects are not only useful in removing and dissi- 

 pating dead animal matter; they are also intrusted with a 

 similar office with respect to the vegetable kingdom. 

 The interior of rotten trees is inhabited by the larva? of a 

 particular kind of crane-fly with pectinated antennas 

 {Ctenophora, Meig.), and other insects, which there find an 

 appropriate nutriment ; and a similar diet is furnished to 

 the grubs of the rose-beetle [Cetonia awata) by the dead 

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

 Staphytinidce, Sphceridia, and other Coleoptera, are always 

 found under heaps of putrescent vegetables ; and an in- 

 finite number are to be met with in decomposing fungi, 

 which seem to be a kind of substance intermediate be- 

 teen animal and vegetable. The Boleti in particular have 

 a genus of coleopterous insects appropriated to them % 

 and the Lycoperdons another. — Stagnant waters, which 

 would otherwise exhale putrid miasmata and be often the 

 cause of fatal disorders, are purified by the innumerable 

 larvae of gnats, Ephemerae, and other insects which live 

 in them and abstract from them all the unwholesome part 

 of their contents. This, Linne says, will easily appear 

 if any one will make the experiment by filling two vessels 

 with putrid water, leaving the larvae in one and taking 

 them out of the other. For then he will soon find the 



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

 more proper than that of Fabricius, Mycetophagns (Agaric-eater), 

 since these insects seldom eat agarics, 



