INDIEECT BENEFITS DERIVED FEOM INSECTS. 219 



away a half-dead snake of about the size of a goose-quill. ^ 

 In fact in the extensive plains of South America and other 

 tropical regions, where ants are both larger and far more 

 numerous than with us, M. Lund conceives that they take 

 the place of the CarahidcB, SilphidcB, and other carnivorous 

 tribes of more temperate climes, there rarely met with, in 

 removing all putrefying animal matter.^ Some insects will 

 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 {Geo- 

 philus electricus). 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 dissipating 

 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 larvae of a particular kind 

 of crane-fly with pectinated antennae (^Ctenophora^), and other 

 insects, which there find an appropriate nutriment; and a 

 similar diet is furnished to the grubs of the rose-beetle ( Ce- 

 tonia aurata) by the dead leaves and stalks usually to be 

 found in the ant's nest. Staphylinidce, SphcBridia, and other 

 Coleoptera, are always found under heaps of putrescent 

 vegetables ; and an infinite number are to be met with in de- 

 composing fungi, which seem to be a kind of substance 

 intermediate between animal and vegetable. The Boleti, in 

 particular, have one genus of coleopterous insects appropriated 

 to them^, and the Ly coper dons 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, EphemercE, and other insects which live in 

 them and abstract from them all the unwholesome part of 



1 It is to be observed that in our cold climates, during the winter months, 

 when excrement and putrescent animal matter are not so offensive, they are left 

 to the action of the elements, insects being then torpid. 



2 Lund in Ann. Sc. Nat, June 1831, quoted in Westwood's Mod. Class, of 

 Ins. ii. 230. 



3 Curtis, Brit. Ent t. 5. 



4 Surely Mr. Marsham's name for this genus, Boletaria, is m.uch more proper 

 than that of Fabricius, Mycetophagus (Agaric-eater), since these insects seldom 

 eat agarics. 



