64 HYMENOPTERA. 



probably prove interesting to pursue the subject a little further, 

 by a few observations on the various species of insects that are 

 parasitic on the VespidcB. The parasites on the Vespidce 

 are numerous, and may be subdivided into three sections: 

 first, vegetable parasites ; secondly, parasites that live inter- 

 nally in both the larval and perfect conditions ; and, thirdly, 

 such as are nourished by feeding upon, and destroying the 

 wasp, in its larval state. 



Not any species of wasp indigenous to this country has 

 been observed to be subject to the attack of vegetable para- 

 sites, but several exotic species commonly suffer thereby ; the 

 PoUstes crinita, from Cayenne, is frequently found to be so 

 much infested by a fungus, which shoots out its spores so 

 luxuriantly into hair-like threads, as to have caused the 

 species to receive several names indicative of the circum- 

 stance, such as P. crinita, P. vegetans, &c. ; this species is 

 best known to science as the PoUstes americanus of Fabri- 

 cius. There are other species belonging to this genus, as 

 well as to the genera Icaria and Pohjbia, subject to this 

 disease of fungoid growth. 



Internal parasites are not uncommonly found in the bodies 

 of our native wasps belonging to the genus Vespa, The 

 hornet is infested by a species of Entozoa, Gordius Vespce 

 crahronis; another species belonging to the genus Spheru- 

 lar^ia, S. Vespce vulgaris, infests the common wasp ; and 

 Dr. Ormerod, in his excellent work on the " Natural His- 

 tory of British Social Wasps," found a species of Gordius 

 infesting it also. 



These attacks, both from fungoid growth and also from 

 tlie presence of Entozoa, there can be little doubt, render 

 the queen wasps incapable of carrying on the business of 

 their economy. 



The next internal parasite to which I have occasion to 



