224 "^^^ Irish Nahiralist. September, 



found six or ^X'^V austriaca queens, and in the outer cells of 

 the same layer forty males whose determination was impossible 

 owing to decay. The circumferential closed cells of the upper 

 layer of comb were tenanted by austriaca males, while rufa 

 males were found in the more internally situated cells. 



From these careful observations, then, Robson concluded 

 that the nest must have been founded by a rufa queen (because 

 typical males and workers of that species were found in it), 

 and that the atistriaca queen, which he had seen dragged out, 

 had subsequently invaded the nest as an inquiline " and util- 

 ized the energies of the workers of V. rufa in rearing her 

 brood of males and perfect females." 



The capture on the wing of many male and female specimens 

 of Vespa austriaca by one of us, at Fenagh, Co. Carlow, and 

 the discovery, in July, 1902, at the same place of a nest, like 

 that examined by Robson, inhabited by both ]/> rufa and 

 F. atistriaca, have led us to examine afresh the question of 

 the relationship between these two wasps. We have made a 

 somewhat careful comparison between many individuals of 

 the two forms, especially with regard to the armature and face- 

 markings of the males, and the mouth-parts of the females ; 

 and we now publish the main results of our inquiry, together 

 with an account of the nest, which was kept for some weeks 

 under observation in a working state. We propose first to re- 

 count the facts that we have been able to verify, and then to 

 suggest the explanation that seems to us the most probable. 



The characters by which Vespa 7'icfa is usually distinguished 

 from F. austriaca are well known to all students of the wasps. 

 The shins of the latter (Plate 2, fig. xi.) are clothed with long 

 hairs not found on those of the former (Plate 2, fig. 11) ; and in 

 the female, as pointed out by Thomson ('74). the tarsal seg- 

 ments are broader in V. austriaca than in V- rufa^ The 

 basal segments of the abdomen in V- rufa (figs. 12-15) are 

 broader than in F. ^?^5/;7<2rfl (figs, xii.-xv.). The male armature 

 in V- rtifa (fig. 6) is broader and darker than in V- atistfiaca 

 (fig. vi.), while the ear-shaped process at the end of the stipes 

 has a characteristic form in either species (compare figs. 8, 



■• But Thomson's statement (writing of V, rufa) " tarsis multo angus- 

 tioribus," seems to us too strongly expressed. 



