1901.] 53 



OBSERVATIONS ON SPHECODES. 

 BY THE REV. F. D. MOEICE, M.A., F.E.S. 



That a couuection of some kind — whether or not it be that of 

 "parasite" and "host" — exists between almost every species of 

 Sphecodes and some one or more particular species of their near 

 relations, the Halicti, can hardly, I think, be doubted by any one who 

 has collected the two genera for any considerable time. Mr. R. C. L. 

 Perkins long ago published two very interesting papers on this subject 

 in the Ent. Mo. Mag. (May, 1887, and Feb., 1889) which, as Mr. E. 

 Saunders says in his " Hi/menoptera Aculeata, &c." (1896), seem to 

 go a long way towards proving the parasitism of Sphecodes. That 

 view, of course, had been put forward long before, but was 

 strenuously resisted by the late Frederick Smith, in his day the chief 

 British authority on such subjects. I cannot but think, however, that 

 Mr. Smith was a little biassed by his interest in the then recent 

 discovery that Prosopis had been unjustly accused of parasitism, which 

 predisposed him to believe that the charge against Sphecodes was equally 

 unjust. On the Continent, as here, authorities have differed on the 

 subject : several eminent French entomologists adopt the parasitism 

 theory ; but Friese (Apidce Europcsce) does not include Sphecodes 

 among his "■ Schmarotzerhienen''' and in the catalogues of v. Dalla 

 Torre and Friese it heads the list of the industrious genera or 

 " Sammelbienen." 



I think it must be owned that nothing like proof positive that 

 Sphecodes is parasitic on HnUctus has yet been produced. No one, 

 that is to say, has reared a Sphecodes from a cell known to have been 

 constructed and provisioned by a Ralictus. But then, the style of 

 nidification adopted by Halictus makes it almost impossible to experi- 

 ment upon its cells with a view to obtaining such evidence. Suppose 

 a cell, resembling the little plain hollow shell of mud constructed by a 

 Halictus, to be dug up successfully from the depths of a bank, to be 

 kept through the summer, and to produce a Sphecodes in the autumn, 

 how after all could we be sure that it had been made and provisioned 

 by a Halictus and not by a Sphecodes f Even if the cell were found 

 in close proximity to others occupied by Halicti, how could it be 

 proved positively that this juxtaposition was not accidental ? 

 Perhaps, then, it would hardly be reasonable to require of the 

 believers in the parasitism of Sphecodes a proof of this kind. And 

 yet, in the absence of such proof, it would seem impossible for their 

 view to advance beyond the state of a more or less probable 

 hypothesis. , 



