:notes ox hymexoptera. 65 



allude has been assigned by several modern entomologists 

 to the order Coleoptera ; it is the Xenos vcspariim of Rossi, 

 who first discovered this class of parasites ; it is closely 

 allied, generically, to that of Stylops, the well-known j)ara- 

 site of the AndrenidcB. This parasite commonly infests the 

 Polhtes gallica, and also Polistes liglumis, both abundant 

 on the continent, but not found in this country. An allied 

 species, Xenos PecJiii, is found commonly in North 

 America. 



I will now proceed to notice such parasites as attack the 

 various species of the genus Vespa inhabiting this country. 

 Vespa crabfOf the common hornet, is attacked by a Coleop- 

 terous insect beloncring to the fimily StaphjUnidWy Quedius 

 dilatatu^,?iii insect of great rarity hitherto, but probably only so 

 because the habitat it frequents is I'ather dangerous of access 

 under ordinary circumstances ; and, as hornets are active by 

 night as w'ell as by day, not even to be approached with 

 impunity, unless the person is clad in an impenetrable garb. 

 The larva of Quedius dilatatus is said to feed upon that of 

 the hornet, and on one occasion I saw a considerable number 

 of dead larvae, doubtless of that species, found in a hornet's 

 nest. I think it very probable that various other parasites 

 infest the nests of this w^asp ; for, as we shall see in the case 

 of the common wasp, Vespa vulgaris, whose economy we are 

 more familiar with, its parasites are numerous. 



Vespa vulgains is subject to the attacks of insects belong- 

 ing to the orders Diptera, Hyraenoptera and Coleoptera. 

 Belonging to the Diptera may be mentioned two species of 

 the genus VoluceUa, V. pellucida and V. homhylans ; in 

 some nests I have found larvee of both these species very 

 abundantly. When the colony of this wasp is attacked, as 

 I have occasionally observed them to be, by a kind of epi- 

 demic dysentery, larvae of some species oi Silpha is commonly 



1871."' " V 



