252 THE FOOD OF ANIMALS 



with annoying impartiality and persistence upon almost all 

 of the many sorts of food which constitute the diet of the mixed 

 feeder, Man. The mouth-parts of this insect are purely suctorial 

 in nature, and lack the piercing stylets which the females of so 



Fig. 463. House- Fly (Musca domestica), enlarged 



many not very distantly related species use with such unpleasant 

 efficiency. 



The members of the large order LEPIDOPTERA, which includes 

 MOTHS and BUTTERFLIES, are almost exclusively vegetarian in 

 habit. The specialized suctorial mouth (see pp. 214, 215) of 

 the adult is adapted for feeding on plant-juices, while the cater- 

 pillar is provided with stout mandibles, which are most efficient 

 biting organs. Yet Carpenter points out (in Insects: Their Struc- 

 ture and Life] that " Butterflies sometimes forsake honey for such 

 unsavoury food as blood from the wound of a mammal or the 

 juices of a putrefying carcass. Several instances are known of 

 caterpillars which eat other insects. The larva of Cosmia trapezina 

 [the Dun-bar Moth] feeds on oak and other leaves, but devours 

 caterpillars smaller than itself which happen to get in its way; 

 while other species are said to prefer insects to leaves whenever 

 the opportunity arises. A small ' looper ' caterpillar has been 

 observed to eat a larva three times as big as itself." In speaking 

 of the Dun-bar Caterpillar, Stainton (in British Moths and Butter- 

 flies) says: "It feeds in May and June on oak, birch, &c., and 

 should be carefully avoided by the collector, as it is extremely 

 apt to devour other larvae that happen to be domiciled with it ". 



