INDIRECT BENEFITS DERIVED FROM INSECTS. 253 



lunaris, Geolrupes siercorarius and many other lamelli- 

 corn insects, make large cylindrical holes, often of great 

 depth, under the heap, and there deposit their eggs sur- 

 rounded by a mass of dung in which they have previous- 

 ly 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 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 Dij)tera, 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 in- 

 deed 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 {Elophilus tenax, Latr.) somewhat resembling a 

 bee. 



Still more would our olfactory nerves be offended, and 

 our health liable to fatal injuries, if the wisdom and good- 

 ness of Providence had not provided for the removal of 

 another nuisance from our globe — the dead carcases of 

 animals. When these begin to grow putrid, every one 



