182 INDIRECT BENEFITS DERIVED FROM INSECTS. 



singular manoeuvres I shall subsequently have to advert to, Copris lunaris, 

 Geotrupes stercorarius, and many other lamellicorn beetles, make large 

 cylindiical holes, often of great depth, under the heap, and there deposit 

 their eggs surrounded by a 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 adjoining 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 convenient passage for a portion of it when dis- 

 solved 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 larvae 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 indis- 

 criminately oviposit in all kinds, some preferring horse-dung, others swine's- 

 dung, others cow-dung, which seems the most favorite 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 

 (Eristalis tenax), 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 

 different sorts of insects attack it, and in various ways. First come the 

 Misters, 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 Casar, &;c.) covering it with mil- 

 lions of eggs, whence in a day or two proceed innumerable devourers. 

 An idea of the despatch made by these gourmands may be gained from 

 the combined consideration of their numbers, voracity, and rapid develop- 

 ment. One female of S. carnaria will give birth to 20,000 young ; and 

 the larvae 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-hundred fold ! In five days after being hatched, they arrive at 

 their full growth and size, which is a remarkable instance of the care of 



characters rides to heaven to petition Jupiter for peace. The play begins with one domestic 

 desiring another to feed the Canthariis with some bread, who afterwards orders his com- 

 panion to give him another kind of bread made of asses' dung. 



' According to M. Robineau Desvoidy, the dung of the badger, which is placed in a 

 separate chamber of its subterranean galleries, has its peculiar fly, which he names Leria 

 melina, the larvae 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 vespertllionea, in like manner, lives in the larva 

 stale on the dung of bats deposited by them at the end of the grottoes of D'Arcy-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 aflTord subsistence. {A?tn. Soc. Ent. de France, x. 255 — 260.) 



