220 INDIRECT BENEFITS DERIVED FROM INSECTS. 



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 water that is 

 full of larvae pure and without any stench, while that which 

 is deprived of them will continue stinking. ^ 



Benefits equally great are rendered by the wood-destroying 

 insects. We indeed, in this country, who find use for ten 

 times more timber than we produce, could dispense with 

 their services ; but to estimate them at their proper value, as 

 affecting the great system of nature, we should transport our- 

 selves to tropical climes, or to those under the temperate 

 zones, where millions of acres are covered by one inter- 

 minable forest. How is it that these untrodden regions, 

 where thousands of their giant inhabitants fall victims to the 

 slow ravages of time, or the more sudden operations of 

 lightning and hurricanes, should yet exhibit none of those 

 scenes of ruin and desolation that might have been expected, 

 but are always found with the verdant characters of youth 

 and beauty ? It is to the insect world that this great charge 

 of keeping the habitations of the Dryads in perpetual fresh- 

 ness has been committed. A century would almost elapse 

 before the removal from the face of nature of the mighty 

 ruins of one of the hard-wooded tropical trees, by the mere 

 influence of the elements. But how speedy its decompo- 

 sition when their operations are assisted by insects! As 

 soon as a tree is fallen, one tribe attacks its bark^, which is 

 often the most indestructible part of it ; and thousands of 

 orifices into the solid trunk are bored by others. The rain 

 thus insinuates itself into every part, and the action of heat 

 promotes the decomposition. Various fungi now take pos- 

 session and assist in the process, which is followed up by the 

 incessant attacks of other insects, that feed only upon wood 

 in an incipient state of decay. And thus in a few months a 



1 CEcon. Nat. Amcen. Ac. ii. 50. Stillingfleet's Tracts, 122. 



2 Maupertuis observes, that in Lapland he saw many birch trees lying on the 

 ground, which had probably been there for a very long time, with the bark entire, 

 though the M^ood was decayed. Hence we may probably infer, that in that 

 country there are few or none of the bark-boring insects. 



