62 FAMILIES OF PETALOCERA WHICH LIVE 



may be observed that all insects intended to live on animal 

 matter partially dispersed and collected in masses, are 

 fiirnished with wings, in order to convey them the more 

 rapidly to the objects pointed out by their instinct. Thus 

 the genera Silpha, Hister, Dermestes, and indeed all other 

 necrophagous insects, are winged; whereas the genera Pi- 

 meliUf Brachycerus, &c., which live like Phoberus on sandy 

 deserts, are apterous, a formation which must arise from the 

 particles of which their food is composed being so univer- 

 sally and generally spread over these plains as to render 

 rapid and distant change of place quite unnecessary. It 

 remains therefore only to consider the nature and econotny 

 ofsuchof the Troges as are provided with wings, of which 

 division are all those hitherto known as European. Oli- 

 vier says of these, that they are to be met with on the 

 ground in the fields, and in sandy and rather dry places ; 

 and that they are sometimes observed on dried animal 

 substances, occupied in gnawing the cartilaginous parts 

 which serve as the last connexion for the bones of car- 

 cases from off which the flesh has been long devoured or 

 consumed. Latreille makes nearly the same remark in his 

 Histoire Generale des Insectes ; and Mr. Kirby mentions 

 in the Introduction to Entomology, his having found these 

 insects on a ram's horn. I was myself present in the forest 

 of Fontainebleau, with the last mentioned entomologist, 

 when he took a specimen of Trox from off a horse's scull ; 

 but it would have been difficult to have discovered either 

 cartilaginous matter or fleshy substance on these bones, 

 which appeared from their colour to have been long exposed 

 to the action of the atmosphere. Indeed nothing can strictly 

 be said to have been determined with respect to the manners 

 of the Troges, except that these insects are attracted to dried 



