210 Mr. F. Smith's and Mr. T. Desvignes' Notes, &;c. 



and that Pimpla oculatoria, Hemiteles paljyator and Ichneumon 

 aranearum are nourished by the eggs of the spiders, and that they 

 undergo their transformations within the spiders' silken cocoon or 

 nest. 



During the past summer I collected a number of the nests of 

 a spider, Agelena brunnea ; these nests may be frequently observed, 

 attached to blades of grass, twigs of heath and other low shrubs ; 

 they are about the size of a cherry-stone, and are composed of 

 beautiful snow-white silk, but coated over with a crust of mud, 

 and thus very closely resemble the nest of a species of solitary 

 wasp, Eumenes coarctatus, only being rather smaller. The latter 

 circumstance has always induced me to examine these nests, 

 but having usually found them filled with spiders, I have not paid 

 much attention to them. On examining one about the middle of 

 June last, I was surprised to find that it contained three or four 

 oblong cocoons, evidently, as I thought, cocoons of some parasite. 

 Having placed the nest carefully in a glass-topped box, I had the 

 satisfaction, in the course of a day or two, to find four specimens 

 of Pczo7nachus fasc'iatus developed ; this circumstance induced me 

 to collect the large number of the spiders' nests, I obtained 

 seventy-three. The following have been the results: I have had 

 in all twenty-two specimens of Pezomachus developed, only in one 

 instance four from one nest, and in six cases three from each. 

 In all the cases in which I obtained Pezomachus, not a single spider 

 was likewise developed. 



Another parasite on the spider appeared in about equal num- 

 bers, but never more than one from a single nest ; in every in- 

 stance, however, four or five spiders were subsequently developed 

 from the same nest as the Ichneumon. 



This latter parasite belongs to the genus Hemiteles, and appears 

 to be a species previously unknown. I am indebted to Mr. 

 Desvignes for having obligingly described the species with great 

 care, under the name of Hemiteles Jbrmosus. 



It appears to me that the fact of the Pezomachus feeding upon 

 the spiders and not on the Hemiteles is clearly proved, as, in the 

 latter case, spiders as well as Pezomachus ought to have been 

 developed ; and when we take into consideration the fact of 

 Pezomachus being quite as bulky an insect as Hemiteles, it can 

 scarcely be supposed that the larva or pupa of the latter could 

 afford nourishment to three or four larvae of the former. 



During the last month not a single insect has been developed, 

 and on opening several of the nests, I found in each, a pupa case 



