164 Mr. W. B. Pickerinff's Observations on 



& 



President was the first English entomologist who described an indi- 

 genous species of this order in his ' Monographia Apum Anglise :' no 

 allusion is made to its economy, beyond the fact of his having ex- 

 tracted the larva and imago from the body of Andrena nigro-cenea, 

 and a suggestion whether the larva whose head is exserted may not 

 feed by absorption. The same learned author, in the British Mis- 

 cellany, states that Mr. Sowerby had suggested to him that what 

 he took for larvae (vide ' Mon. Apum Anglic,') were really pupte; add- 

 ing, " To this ingenious conjecture I readily accede, as it removes all 

 the difiiculty with respect to their mode of feeding, the larva being 

 entirely within the body till it is ready to assume the pupa state, then 

 exserting its head at the dorsal inosculations of the abdominal seg- 

 ments so that the perfect insect may the more readily disengage it- 

 self when its time for disclosure is come." The pupae are generally 

 in pairs ; these, it is suggested, may probably be the sexes. He wishes 

 he could point out where collectors might meet with these insects, 

 and thinks that by ascertaining in what state of the Melitta the Sty- 

 lops deposits her egg, entomologists might be enabled to capture 

 these desirable insects. In a paper published in the Linnsean [Trans- 

 actions by the same author on the propriety of forming these .Tisects 

 into an order, he gives some extracts from a letter which he had 

 received from Mr. Peck of America, which as they relate to the 

 economy of Xenos Peckii I must here notice. " The abdomens of 

 the Vespcs were so distorted that he could distinguish them when 

 on the wing ; he caught some specimens of the wasps, fed them with 

 sugar, and by this means obtained specimens of Xenos : he found by 

 dissection that the head of the larva was in the feeding state turned 

 towards the base of the abdomen of the wasp. When the feeding 

 state is over, he conceives that the larva turns, and with its flattened 

 head separates the membrane that connects the abdominal seg- 

 ments, and protrudes a little out. The head of the larva when first 

 exserted is of a pale brownish colour, but by degrees assumes a 

 rounder form and becomes almost black. Mr. Peck also notices the 

 particular termination of the last segment of the abdomen of the 

 imago, inquiring if it is a kind of aculeus for depositing its egg in 

 the larva vespa, for it is in the larva that the eggs are probably de- 

 posited," To this Mr. Kirby adds as a note : " Reasoning from 

 analogy it seems not probable, though I formerly inclined to this 

 opinion, that the eggs should be laid in the wasp in its first state, 

 and the larva feed on it to the last." 



M. Jurine in his observations on Xenos, remarked that male as well 

 as female wasps were attacked ; discovered the larva entirely within 

 the abdomen of the wasp when not visible externally, and that the 

 head of the larva was turned towards the apex of the abdomen ; 



