62 



[March, 



ON AN OVEELOOKED NEW SPECIES OF HALICTUS IN BEITAIN. 

 BY R. C. L. PEllKIXS, D.Sc, M.A., F.Z.S. 



As lono- ago as 1886 I was aware of the fact that we had two forms 

 standing- under the name of R. qnadrinotatns, Kh'by, these fonns differ- 

 ing slightly in superficial characters. Both were sent at that time to 

 Edward Saunders, but he did not attribute any importance to the 

 characters exhibited. Recently, on my return to England, I again 

 observed both forms in company at Dawlish, and felt satisfied that we 

 had to deal with two distinct species, and the examination of the male 

 genitalia proves this opinion to have been correct. 



In general appearance and structure the two species are practically 

 identical so far as I can see, excepting that in the one the nervure bor- 

 dering the stigma beneath is conspicuously dark, in the other pallid 

 and nearly concolorous with the stigma itself. Kirby's few type 

 specimens contain both forms under the same number, and his 

 description would practically apply to either, but on account of the 

 slightly more pallid neuration of the form with the ])ale stigmatic vein 

 I am inclined to take this as quadrinotatus, Kirby. His remark on the 

 neuration is : " nervis costali interiorl nigro excepto testaceis." For the 

 form with the lower margin of the stigma dark- I should propose the 

 name H. decipiens. 



H. deci'piens, sp. nov. 

 Stigma in both sexes with dark lower 

 margin. 



(J with the lacinia of the genital 

 armature overliving by a dense 

 clothing of long hairs. 



'^ with the apical margin of the first 

 abdominal segment generally less 

 densely and evenly pvmctured. 



H. quadrinotatns, Kirby. 

 Stigma in both sexes concolorous or 

 nearly so throughout. 



(J Avith the lacinia of the genital 

 armatiu'e with a fringe, and not 

 concealed beneath long hairs, the 

 apical portion of the stipites glab- 

 rous. 



? with the apical mai-gin of tlie first 

 abdominal segment very densely 

 pimctured, contrasting strongly 

 with the discal punctui-ation. 



The figure of the genital armature in Saunders' " Synopsis " was, 

 no doubt, taken from the species here considered as true H. 4-notatus, 

 Kirby. Apart from their length and density, the hairs of the armature 

 of H. decqnens under high powers of the microscope are of remarkable 

 structure. In tig. 1 the magnification used was not sutiicient to show 

 the minute structure of the hairs. Owing to the strong curvature 

 downwards of the apical portion of the armature the appearance of the 



