ii FOOD OF INSECTS 41 



a wonderfully great protection from those most trouble- 

 some pests, one in a sense superior to all the arti- 

 ficial methods of prevention that were ever devised, 

 inasmuch as they cost us absolutely no trouble and no 

 expense. The balance of life between vegetables, in- 

 sect pests, and their parasites is indeed extraordinary, 

 and we cannot be too careful of instituting measures 

 tending to upset, even ever so little, nature's ap- 

 pointed ways. 



Not only animals themselves, animal matters in 

 great variety constitute the food of many insects. 

 Hair, wool, leather, silk, fur, even feathers, are not de- 

 spised, and the grub of a beetle, with powers of diges- 

 tion that a dyspeptic might envy, can subsist on horn. 

 The larva of a moth popularly styled the Tabby 

 (Aglossa pingiiinalis}, known both in houses and 

 stables, has the still more remarkable fancy for grease 

 in any shape or form for greasy horse-cloths, kitchen 

 fat, and so on and nothing could be more interesting 

 and instructive than the marked adaptation of its 

 structures for the mode of life it adopts. Its habit is 

 to feed by diving into the food-stuffs bodily. It is in 

 no danger of being suffocated, for its breathing ap- 

 paratus is arranged to prevent the fat from clogging 

 its pores. Kitchen fat and horse-cloths are products 

 of a more or less recent civilisation, and probably no 

 one will deny that these larvae have acquired their 

 peculiarities, enabling them to obtain food under such 

 extraordinary conditions, at a period subsequent to 

 the introduction of the fatty materials in question 

 In a word the moths are a new species, evolved from 

 ancestors which led different lives. To reject this 



