280 ENTOMOLOGY 



Diptera and Coleoptera derive their food from dead animal 

 matter. The aquatic families Dytiscidse and Gyrinidse are 

 largely scavengers. Among terrestrial forms, Silphidae feed 

 on dead animals of all kinds; the burying beetles (Necroph- 

 orus), working in pairs, undermine and bury the bodies of 

 birds, frogs and other small animals, and lay their eggs in the 

 carcasses ; Histeridse and Staphylinidse are carrion beetles, and 

 Dermestidse attack dried animal matter of almost every de- 

 scription, their depredations upon furs, feathers, museum 

 specimens, etc., being familiar to all. Ants are famous as 

 scavengers, destroying decaying organic matter in immense 

 quantities, particularly in the tropics. Many Scarabseidse feed 

 upon excrementitious matter, for example the " tumble-bugs, " 

 which are frequently seen in pairs, laboriously rolling along or 

 burying a large ball of dung, which is to serve as food for the 

 larva. 



Insects as Food for Vertebrates. Lizards, frogs and 

 toads are insectivorous, especially toads. The American toad 

 feeds chiefly upon insects, which form 77 per cent, of its food 

 for the season, the remainder consisting of myriopods, spiders, 

 Crustacea, molluscs and worms, according to the observations 

 of A. H. Kirkland, who states that Lepidoptera form 28 per 

 cent, of the total insect food, Coleoptera 27, Hymenoptera 19 

 and Orthoptera 3 per cent. The toad does not capture dead 

 or motionless insects but uses its extensile sticky tongue to lick 

 in moving insects or other prey, which it captures with sur- 

 prising speed and precision. In the cities one often sees many 

 toads under an arc-light engaged in catching insects that fall 

 anywhere near them. Though its diet is varied and some- 

 what indiscriminate, the toad consumes such a large propor- 

 tion of noxious insects, such as May beetles and cutworms, 

 that it is unquestionably of service to man. 



Moles are entirely insectivorous and destroy large numbers 

 of white grubs and caterpillars ; field mice and prairie squirrels 

 eat many insects, especially grasshoppers, and the skunk rev- 

 els in these insects, though it eats beetles frequently, as does 



