March, 1900. 1 



49 



FROSOPIS PALUSTRIS, sp. Nov., AN ADDITION TO THE BRITISH 

 EYMENOPTERA. 



BY R. C. L. PERKINS, B. A. 



I have included this species in the ubiquitous genus Prosopis 

 with some hesitation, because in nearly all its characters it might 

 quite well be associated with the fifty odd Hawaiian species for which 

 I recently made the genus Nesoprosopis. At present, however, I have 

 not been able to examine the characters sufficiently minutely to be 

 sure that it would be correct to place the species in that genus, 

 although certainly in many of the most important structural points 

 it is so exactly similar to Nesoprosopis that no doubt can be felt that 

 at any rate it is really very closely allied thereto. The form of the 

 8th ventral segment with its large erect process, and the manner in 

 which it is given off from the body of the segment, the depressed 

 sides of the face in the (^, the form of the propodeum, &c., are all 

 noticeable characters in both this and the Hawaiian species. Hitherto 

 the species known to me, which most nearly approached Nesoprosopis, 

 was the European P. cornufa, but the process of the 8th segment of 

 the (^ in that species arises in a different manner (the many Hawaiian 

 species never differing in this point), and the genitalia are also very 

 different. So far as the Bi'itish species are concerned, P. iJaJustris is 

 amongst the largest, and cannot easily be confused with any other. 

 The female superficially resembles P. communis, but the impunctate 



basal segment of the abdomen easily distinguishes it, and the structure 

 of the propodeum is essentially different, being less abrupt posteriorly, 

 and in P. communis the posterior elements are much more widely 

 separated by the backward [)roloiigation of the anterior area. 



