including a Hymenopterous Parasite, 237 



narrow portion of the nidus, in which the eggs were depo- 

 sited, was divided from the broader by a silken curtain of the 

 same material as the external portion ; within this were the 

 remains, apparently, of some larvae, one or two of which were 

 also in the superior cavity ; but of the nature of these, even 

 with the aid of a high magnifier, I could form no satisfactory 

 opinion. 



1 opened another nest, but in that there was no occupant ; 

 and the nest of eggs at the upper end was firmly agglutinated 

 together, having a convex surface ; whereas, in the former, the 

 shapeless masses which I observed were scattered. On hold- 

 ing the other specimens to a strong light, they appear per- 

 fectly transparent at the broad, and opaque at the narrow, end, 

 exhibiting no appearance of any inmate. 



At first I was disposed to think I had discovered a new 

 fact in entomology, and began to adjudge the merits of the 

 construction of so beautiful a piece of architecture to the 

 hymenopterous insect. Doubts, however, sprang up in my 

 mind, which were confirmed on turning to your pages, where 

 I found Mr. Kirby decidedly of opinion that the nidus was 

 the work of a spider, and that your correspondent W. B. B. W. 

 (Vol. III. p. 458.) asserted his having reared spiders from 

 analogous nests. On consideration, it was obvious that, if 

 the hymenopterous insect were the architect, and the nest had 

 been finished on the internal side, each would have been 

 inhabited ; I therefore came to the conclusion that the insect 

 I found was a parasite. 



Till I had commenced this paper, it did not occur to me to 

 refer to Kirby and Spence ; but, on doing so, I find those 

 authors allude to the subject in the chapter on the diseases 

 of insects, wherein they describe the attacks of those /chneu- 

 monidae which are parasitical on eggs. They state, " Though 

 the animals we are speaking of usually destroy only a single 

 ^gg, yet some appear not so to confine themselves. GeofFroy 

 informs us that the larva of one of the ichneumons whose 

 females are without wings (Cryptus Fab.) devours the eggs of 

 the nests of spiders, and from its size (it is nearly a quarter 

 of an inch long) it must require several of them to bring it 

 to maturity." [Geoff. Hist, Ins., par. ii. 361. Kirby and Spence, 

 vol. iv. p. 218.) That the insect so mentioned by Geoffroy 

 is the same, or at least congenerous, with the one I have dis- 

 covered, I do not doubt ; more especially as he refers to the 

 female being apterous : but I am inclined to believe that, 

 in the nidus I have described, the larvae have been hatched, 

 and that the loose and light portions in the inferior cavity are 



