20 



have in view, it is necessary or convenient to do so. On the other hand 

 the insect Parasite, and the insect Cannibal and the human cannibal 

 desire the bodies of their victims as food for themselves, and are 

 necessarily obliged to slay, because it is only by inflicting death upon 

 others that they can satiate their own carnivorous appetites. 



In the case of the Grape Curculio, as in many other such cases, 

 there is more than one species of Guests sponging upon a single Host. 

 I find that two very distinct larvse — one of them belonging to the same 

 Order as tlie Curcnlio, (the Colcopicra or beetles,) but to a very widely 

 distinct Family, the other to an entirely different Order (the Dip- 

 tera or Two-winged Flies) — occupy the grapes after they have been 

 tenanted by the Curculio, and derive their subsistence therefrom. 

 Whether these spongers upon the fruits of other Bugs' labors dwell 

 as co-tenants with them in the larva state, I do not know. Perhaps 

 they do not; at all events they do not do so for any considerable time. 

 But most certainly the eggs, from which the intruding guests spring, 

 must be deposited in the infested grape by the mother-insect before 

 the larva of the Curculio leaves it; for my infested grapes contained 

 the Curculio larvas when I received them from Ohio, and were there- 

 after isolated in a closed vase, to which the mother of the Guest- 

 larvae could gain no possible access. As one species of these guests 

 arrived at the perfect state about six weeks, and the other about eleven 

 weeks after the Host, it is likely enough that the eggs of both of them 

 were deposited in the wounded grape, not very long before the larva 

 of the Grape Curculio was ready to descend to the earth and leave a 

 clear stage for the operations of his successors ; and that consequently 

 these eggs did not hatch out till about the time that the spoiled 

 grape was vacated by its original tenant. 



The former of the two Guests just now referred to is the Twin- 

 spotted Nitidula {Sielidota geminata. Say) — a flatfish, oval beetle, of 

 an obscure brown color with dull yellow markings, and rather less than 

 one-tenth of an inch long. It belongs to a somewhat extensive group 

 (the Nitidula family), all of which feed in the larva state upon de- 

 caying animal or vegetable substances, and several of which may 

 be often met with in decaying cheese, old half -picked bones, old sheep- 

 pelts, etc. Of this insect, from some fifty infested grapes, I bred 

 October 12th — 20th no less than thirty-three specimens. So that 

 manifestly their occurring in such grapes was not a mere casual 

 phenomenon, but part of the regularly pre-ordained system of Na« 

 ture. Kature, indeed, in whatever direction we turn our eyes, is al- 

 ways economizing and utilizing what would otherwise be uselessly 

 expended, and she cries aloud everywhere to those who know how to 



