226 INDIRECT BENEFITS DERIVED FROM INSECTS. 



services and those of the Egyptian Ichneumons (Viverra 

 Ichneumon), the former as destroyers of insects, being equally 

 important with the latter as devourers of serpents, the eggs 

 of crocodiles, &c. 



The habits of the whole of this tribe ^ which properly in- 

 cludes several families (^Ichneumonidce, Chalcididce, &c.) and 

 a great number of distinct genera, are similar. They all 

 oviposit in living insects, chiefly while in the larva state, 

 sometimes while pup^e (Misocampus Puparum); at others 

 while in the e^^ state {Pteromalus ovulorum, and bifasciatus, 

 Chrysolampus tristis, &c.). The eggs thus deposited soon hatch 

 into grubs, which immediately attack their victim, and in the 

 end insure its destruction. The number of eggs committed 

 to each individual varies according to its size, and that of 

 the grubs which are to spring from them ; being in most 

 cases one only, but in others amounting to some hundreds. 



From the observations hitherto made by entomologists, the 

 great body of the Ichneumon tribe is principally employed in 

 keeping within their proper limits the infinite host of lepido- 

 pterous larvae, destroying, however, many insects of other 

 orders ; and, perhaps, if the larvae of these last fell equally 

 under our observation with those of the former, we might 

 discover that few exist uninfested by their appropriate para- 

 site. Such is the activity and address of the Ichneumonidans, 

 and their minute allies {Pupivora Latr.), that scarcely any 

 concealment, except, perhaps, the waters, can secure their 

 prey from them; and neither bulk, courage, nor ferocity 

 avail to terrify them from effecting their purpose. They 

 attack the ruthless spider in his toils ; they discover the re- 

 treat of the little bee, that for safety bores deep into timber ; 

 and though its enemy Ichneumon cannot enter its cell, by 

 means of her long ovipositor she reaches the helpless grub, 

 which its parent vainly thought secured from every foe, and 

 deposits in it an egg, which produces a larva that destroys it.^ 



1 Latreille denominates this family, as he calls it, Pupivora : if by this he 

 alludes to their devouring the young of insects, from the classical meaning of the 

 Avord pupa, the term is very proper ; but this should be borne in mind, as the 

 majority of readers would imagine it to refer to thepupa state of insects, in which 

 they are not so generally devoured by their parasites. 



2 Marsham in Linn. Trans, iii. 26. 



