252 [November, 



PS EN CONCOLOR, Dahibom : 



A NEW BEITISH FOSSORIAL ACULEATE. 



BY THE RET. P. D. MOBICE, M.A., F.E.S. 



The only species o£ Psen at present on the British list is pallipes, 

 Panz. (= atratus, Dahlb., Thorns., Andre, &e.), but I am now able to 

 add a second, viz., concolor, Dahlb., of which I took a ? on June 14th 

 o£ this year at Byfleet. I did not record the capture at the time, as 

 I hoped to find both sexes. But evidently, for this season at least, 

 that hope must be abandoned, so it seems useless to delay this notice 

 any longer. 



Psen concolor is very like a large example of pallipes, but there is little diffi- 

 culty in distinguishing the two species. They differ most conspicuously in the 

 sculpture of the head, and especially of the tubercle or carina between the antennae. 

 (1) This, in pallipes, is shaped like an inverted T — *• «■> the lateral branches of the 

 carina start from a point decidedly lower in the face than the insertions of the 

 antennae, and run past these, transversely, towards the eyes ; whereas in concolor 

 the form is rather that of an inverted Yj the branches running obliquely, rather 

 towards the "genae" than the eyes, starting higher up between the insertions of the 

 antennae, and hardly extending beyond them. (2) The face of concolor below the 

 tubercle is foveated, while in pallipes it is flat or, if anything, a little convex. (3) 

 The base of the longitudinal carina in pallipes is much more dilated than in concolor ; 

 and is excavated above into a wide, nearly square, or rather " lozenged," fovea, which, 

 in concolor, is represented only by a narrow longitudinal groove. (4) The brow, 

 from the antennae and the tubercle upwards to the ocelli, is smooth and shining in 

 concolor ; in the other species it is much duller, and somewhat rugose, the punctura- 

 tion also is far coarser. 



Thomson points out another character in connection with the (exterior) pair of 

 longitudinal impressed lines on the mesonotum. These in concolor are very long 

 (" ultra medium extensis "), while in pallipes they are short and inconspicuous. 

 My specimen shows this character strongly. 



While examining ray insect in search of other characters, I noticed that its 

 apical ventral segments were not fringed, as in fresh examples of pallipes, with 

 silvery sericeous hairs. I was not sure, at first, whether this was a specific difference, 

 or merely a consequence of " rubbing " in the particular insect. But, as the speci- 

 men appeared to be in very good condition, 1 concluded for the former alternative, 

 and I now find that the absence of these fringes is mentioned by the late Edm. 

 Andre (Species, vol. iii, p. 183) as characteristic of concolor. 



The (J of concolor I have never seen, but it must be instantly recognisable by its 

 brow, which is smooth and shining, as in the ? . I gather, too, from the descrip- 

 tions of it given by Ihomson, Tournier, and Andre, that it has also the branches of 

 the frontal carina oblique; though only the last of these authors positively says so. 

 Dahibom, however (Sphex, Suppl., p. 429), says, on the contrary, that these "ramuli," 

 though oblique in the $ , are transverse in the ^. In his original description of 

 the species (Sphex, p. 6), he speaks as if the (J was as yet unknown to him. 



