96 
NATURAL HTSTORY OF 
season of the year by a rapid evaporation, and the 
smaller streams at one time undergo the same fate, 
and at another assume the character of torrents. 
As providence in the creation of insects seems 
partly to have designed them for removing various 
nuisances and superfluous materials from the face 
of nature, their distribution is regulated accordingly, 
and their numbers proportioned to the work assigned 
to them. In temperate climates, for example, where 
the dead carcasses of animals decompose but slowly, 
our senses would be continually offended, and our 
health liable to injury, from the unwholesome mias- 
mata that exhales from them, unless some»pro vision 
were made to accelerate their removal. We ac- 
cordingly find a profusion of carcass-eating beetles 
— Necrophori , Silphidce , &c. — which speedily as- 
semble from all quarters, round a dead body, led by 
the emanation of the tainted air, and in a short pe- 
riod it is either buried or consumed. In several 
extensive countries of South America, however, 
where the extreme dryness of the air and heat of the 
sun cause the animal juices to evaporate with such 
rapidity that a dead body can scarcely be said to 
putrefy, but is converted into a substance so com- 
pletely desiccated, that travellers across the woodless 
pampas sometimes make their fire of a dead horse, 
such insects would scarcely be required, and ac- 
cordingly few if any have been observed. In this 
country, and others under similar latitudes, nature 
has devolved the task of removing excrementitious 
