354 PHYSIOLOGY. 



But more important than these differences, derived from the external 

 quality of their nutriment, are those which refer to their being either 

 of vegetable or animal origin. Thus the food of insects may be divided 

 into two groups, so that we can class it into four different kinds, each 

 of which again admits of subdivision, according to whether it be fresh 

 or whether putrefaction have already commenced, which we thus 



arrange :- 



I. From substances requiring comminution. These are, 

 1. Of the ANIMAL KINGDOM, and are, 



a. Fresh and uncorrupted, and generally consisting of living 

 individuals obtained by force. 



The predaceous beetles, viz., the Cicindela;, Carabodea, 

 Hydrocanihari, and Staphylini, support themselves by this 

 kind of food. All devour other insects, chiefly larvae, which 

 they obtain by capture, or the flesh of dead and fresh verte- 

 brata to which they can procure access. Some, as the Dytici, 

 are said to attack living fish, and eat out their eyes; others, 

 as Hydrophili, devour the spawn of fishes and frogs, and 

 even such young frogs and tadpoles as they can master. 



b. Animal substances in which putrefaction has already com- 

 menced, particularly carrion. 



The large family of carrion beetles (Peltodea), especially 

 feed upon such substances. Their larvae live wholly in pu- 

 trescent vertebrata, and devour their flesh, and the perfect 

 insect also derives its nutriment from it. The burying 

 beetle (Necrophorus} buries small vertebrata, depositing its 

 eggs in their body ; thus innumerable carcases are destroyed. 

 Smaller beetles, for example, the Aleochara, many Sta- 

 phylini., Corynetes, &c. assist them in this business. Others, 

 again, consume only the dried skins of animals and their 

 clothing, as the fur beetles (T)ermestoAed) and the clothes 

 moths ( Tinea pellionella, &c.). 



c. Excrementitial substances, animal excrements. 



The majority of onthophagous insects are extremely fond 

 of the excrements of the herbivora. But this cannot be con- 

 sidered as distinctly animal or vegetable matter, but as an 

 intimate mixture of both ; therefore all beetles which devour 

 such excrements are fed upon both animal and vegetable 

 substances. To these belong all the onthophagous Pdalocera, 



