October, lOOS.l 237 



The following is a complete inventory of tlie nest : — 



Perfect Insects. 



Queens 1 austriaca (old). 



8 austriaca (young). 



Workei's 86 rufa . 



Males 46 austriaca. 



3 rufa. 



2 rufa, approatfhing austriaca. 



PUPTE. 



Queens 3 austriaca. 



5 indistinguishable. 

 Males 6 austriaca. 



11 rufa, approaching austriaca. 



14 indistinguishable. 



A B 



St... 



Fisr. A. Male armature of Dombus lapidarhts, Linn. ^ .it. stipes. 

 B. ,, ,, Psithi/rus rupestris, F.ib. J see. sagitta. 



After Saunders. Magnified 10 times. 



Our comparative study of the structure and markings of Vespa rufa and V. 

 austriaca has convinced us that the relationship between tlio two wasps is so very 

 close that it must of itself raise a doubt as to the generally accepted view of the 

 connection between the two being merely that of host and inquiline. We are in 

 complete agreement with the opinion of Andre ('84), that no justification whatever 

 is afforded by structural characters for the removal of V. austriaca into a distinct 

 genus. The closeness of its kinship to Y. rufa may be appreciated by comparing 

 the male armature of these two wasps (Plate, figs. 6, vi) with the corresponding 

 parts in a Bomhus and the Psithyrus which lives as its inquiline (figs. A, B). 

 Bombus and Psithyrus are not very widely separated from each other ; indeed, they 

 are probably more nearly akin than any two genera which stand in tlie relationship 

 of host and guest. Yet the armature in these two bees shows a marked distinction 

 as compared with the slight comparative differences in our two wasps. Compare 

 the large terminal segment of the stipes and the short falcate sagitta in Psithyrus 

 with the corresponding parts in Bomhus. 



On any view as to their habits, the structure of Vespa rufa and V. austriaca, 

 and the fact that each form varies in the direction of the other, show that they 

 must have diverged from a common stock in comparatively very recent times. The 

 observations that we have been able to make on the nest containing both forms 



Y 



