INDIRECT BENEFITS DERIVED FROM INSECTS. 147 
called in America the Yumbledung, whose singular manceuvres I shall 
subsequently have to advert to, Copris lunaris, Geotrupes slercorarius, and 
many other lamellicorn beetles, make large cylindrical holes, often of 
great depth under the heap, and there deposit their eggs surrounded bya 
mass of dung in which they have previously enveloped them; thus not 
only dispersing the dung, but actually burying it at the roots of the ad- 
joining plants, and by these means contributing considerably to the fertility 
of our pastures, supplying the constant waste by an annual conveyance 
of fresh dung laid at the very root ; by these canals, also, affording a con- 
venient passage for a portion of it when dissolved to be carried thither by 
the rain. 
The coleopterous insects found in dung inhabit it in their perfect as well 
as imperfect states ; but this is not the case with those of the order Diptera— 
whose larvee alone find their nutriment in it; the imago, which would be 
suffocated did it attempt to burrow into a material so soft, only laying its 
eggs in the mass. These also are more select in their choice than the 
Coleoptera — not indeed as to delicacy, — but they do not indiscriminately 
oviposit in all kinds, some preferring horse-dung, others swine’s-dung, 
others cow-dung, which seems the most favourite pabulum of all the dung- 
loving insects, and others that of birds. The most disgusting of all is 
the rat-tailed larva that inhabits our privies, which changes to a fly (Zris- 
talis tenav), somewhat resembling a bee. 
Still more would our olfactory nerves be offended, and our health liable 
to fatal injuries, if the wisdom and goodness of Providence had not pro- 
vided for the removal of another nuisance from our globe —the dead 
carcasses of animals. When these begin to grow putrid, every one knows 
what dreadful miasmata exhale from them, and taint the air we breathe. 
But no sooner does life depart from the body of any creature, at least of 
any which from its size is likely to become a nuisance, than myriads of 
diferent sorts of insects attack it, and in various ways. First come the 
Histers, and pierce the skin. Next follow the flesh-flies, some, that no 
time may be lost (as Sarcophaga carnaria, &c.), depositing upon it their 
young already hatched; others (Musca Cesar, &c.), covering it with 
millions of eggs, whence in a day or two proceed innumerable devourers. 
An idea of the dispatch made by these gourmands may be gained from the 
combined consideration of their numbers, voracity, and rapid development. 
One female of S. carnaria will give birth to 20,000 young ; and the larve: 
of many flesh-flies, as Redi ascertained, will in twenty-four hours devour 
so much food, and grow so quickly, as to increase their weight two 
hundredfold! In five days after being hatched, they arrive at their full 
growth and size, which is a remarkable instance of the care of Providence 
* According to M, Robineau Desvoidy, the dung of the badger, which is placed in 
4 separate chamber of its subterranean galleries, has its peculiar fly, which he names 
Leria melina, the larve of which there feed upon it; and the parent flies never 
ascend to the surface, but constantly reside in this dark and damp abode, and can 
only be obtained by digging into it. Another fly, his Thelida vespertilionea, in like 
manner, lives in the larva state on the dung of bats deposited by them at the end of 
the grottoes of D’Arey-sur-Eure more than one hundred toises distant from their 
entrance; and he describes a third fly, Leria mustelina, which he believes to feed on 
the dung of the weasel, and names other distinct species to which the dung of the 
fox, the rabbit, the water-rat, and the field-mouse respectively afford subsistence, 
(Ann. Soc. Ent, de France, x. 255-260.) 
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