286 [December, 



WHAT WAS SPHEX XANTHOCEPHALA, Forster 



(A British Insect, but ignored in British Lists) ? 



BY THE REV. P. D. MOEXCE, M.A., F.E.S. 



So long ago as in 1771 the once-celebrated author and traveller 

 J. R. Forster — deserving to be remembered inter alia as the naturalist 

 who accompanied Cook on his second voyage— published in London 

 the description of a black and yellow fossorial wasp, which he named 

 as above, and whose habitat he gives as " Anglia." The description — 

 with certain not unimportant omissions — was reproduced by Gmelin 

 in hi? edition (1790) of " Systema Natnrse," but it seems to have 

 entirely escaped the notice of British authors, and I can find no 

 allusion to such an insect in the works of Shuckard or F. Smith or 

 E. Saunders. It is mentioned, however, with a note of interrogation 

 prefixed, in v. Dalla Torre's Catalogue as possibly synonymous with 

 Phihmtlius triangulum, F. ; and if this identification could be estab- 

 lished, the latter well known Dame would have to be abandoned, since 

 the earliest description of triangulum was in 1775 — four years later 

 than the publication of xantlwcepliala. But I think it is demonstrable 

 that xanthocepliala was not triangulum, but a much more common 

 British insect, whose name is fortunately unalterable, having been 

 fixed by Linne in 1758 in the 10th edition of " Systema Naturse." 



Forster's description, though naturally based almost exclusively 

 on colour-characters, is very careful and full of detail. He tells us 

 that the size of the insect was that of Crabro cribrarius, L. ; that the 

 apices of the wings were ' fuscescentes ' (which can hardly be said of 

 triangulum), and that the basal joint of the antennae was yellow (in 

 triangulum, except in some quite southern forms, it is generally 

 entirely black, or at most bears a small yellow spot which easily 

 escapes notice). But the description of the abdomen makes it, I 

 think, quite clear that the insect in question is not triangulum. It 

 runs thus : " Abdomen nigrum ; margines segmentorum 2, 3, 4, 5, 6 

 fasciis flavis cincti, subtus puncta flava utrinque duo." This, as I 

 read it, can only describe an insect with the basal segment of its 

 abdomen entirely black, and with the segments following belted each 

 with yellow at the apical margin only of its dorsal plate, while, on the 

 ventral side, the abdomen is black entirely except that two of its plates 

 have roundish spots (puncta !) on their sides. Now having examined 

 countless foreign specimens and several British ones of triangulum, 

 both <§ J and ? ° , I have never seen among them anything at all 

 resembling the above coloration. Even in the darkest forms, the basal 



