PARASITE EGGS. 59 



Another parasite (Pimpla strobilellce, Fabr.) is 

 armed with a long ovipositor, with which it deposits 

 its eggs in larvae, that burrow in the fruit-cones of 

 the fir. 



The intrusion of these parasite eggs into the nests 

 of insects is often an exceedingly puzzling circum- 

 stance to naturalists, in their earlier researches; and 

 sometimes even deceives those of considerable expe- 

 rience and acuteness into the supposition that the 

 insects ultimately produced are in reality those of 

 the original builder of the nest. These deceptions 

 frequently occur in the numerous species of vege- 

 table galls, originating chiefly in the economy of a 

 beautiful family of insects {Chalcididce, Westwoob). 

 When the gall-fly ( Cijnips) has deposited its eggs on 

 the bud or the leaf of a plant in such a manner as to 

 insure their being surrounded with a thick coating of 

 vegetable substance, they are not on that account se- 

 cure from the insects just alluded to; for the Chalcis, 

 armed by nature with an instrument for the purpose, 

 can penetrate in any direction the largest oak-apple 

 or bedeguar of the rose.* The most obvious distinc- 

 tion between these parasites and the true gall-flies, is, 

 that in the latter the ovipositor is partly concealed, 

 while in the former it is altogether external, like the 

 ichneumons in the preceding figure ; but this dis- 

 tinction is of course wanting in the male insects. It 

 was the observation of difterent species of insects, 

 produced in this manner from the same sort of gall, 

 which betrayed the illustrious Redi into the fanciful 

 notion of their being generated by a vegetative and 

 sensitive soul in the plant itself, to which also he attri- 

 buted the generation of the grubs found in nuts, cher- 

 ries, and other fruits. ' There is nothing,' as Reau- 

 mur justly remarks, ^more fitted to humihate the best 

 reasoners, and to inspire them with a well-founded 



* See Insect Architecture, pp. 375 — 384, 



