322 PTILOTA : PHYSIOLOGY AND 



If, on the other hand, we direct our attention to the pre- 

 servation of the individual (and many of the peculiarities of 

 social insect life conduct us to this branch of our inquii-y), 

 we find the subject also divides itself into two sections, 

 namely, the various stratagems employed for obtaining a 

 supply of food, and the means of active or passive defence 

 adopted by insects. With a few notices of some of the most 

 remarkable of each of these instinctive pecuharities, I shall 

 close the present branch of our subject. 



We have seen in the early part of this work that, from 

 the very nature of the functions of the insect tribes, it is es- 

 sential that the consumption by them of animal and veget- 

 able matter should uninterruptedly be carried on. Hence, as 

 well as from the nature of insects m general, and the great 

 care showTi by the female in depositing her eggs in the most 

 fitting situations, there is but little occasion for any exhibition 

 of instinctive reasoning on the part of these animals, with 

 the exception of those which prey upon living animal matter. 

 Here pursuit, search, or some equivalent thereto, is neces- 

 sary for insuring a due supply of food ; and hence we find 

 that the predaceous tribes of insects, like their analogues 

 among beasts or birds, are more fitly organized for rapid 

 movements than the lazy inactive herbivorous species. If 

 this be the case with the perfect insects, there must be some 

 other mode of obtaining their food by their predaceous larvae 

 (especially since it is during this period that feeding is the 

 great object of an insect's existence), which are not furnished 

 with sufficiently powerful organs of locomotion. The extra- 

 ordinary mask of the larva and pupa of the dragon-flies, ex- 

 hibited both at rest and in action in the accompanying figures, 

 is a most admirably contrived instrument applicable for such 

 purpose ; and the raptorial structure of the fore-legs of many 

 predaceous insects, the great strength of muscles by which 

 these organs are moved, and the many strong spines with 



