BY REV. T. BLACKBURN. 505 



from each other by the sculpture of the pronotum, which in the 

 Second Subgroup bears in both sexes on its hinder half a carina 

 extending (sinuously or not) in a curve (the general convexity of 

 which is hindward) from, or from close to, the sublateral fovea on 

 the one side to the corresponding part of the other side; while in 

 the other Subgroup there is no such carina in either sex. I have 

 placed the Subgroup in which this prothoracic carina is wanting 

 before the other, because it contains numerous species in which 

 the difference between the sexes is very much greater than in any 

 species of the other Subgroup, and the most natural arrangement 

 of the Australian Bolbocerata seems to be attained by regarding 

 the degree of sexual difference and the size of the insects as the 

 best index to the specific development; and by the arrangement 

 proposed above we begin with the largest species having the 

 strongest sexual characters (in the First Group), and find these 

 characters and also the size gradually becoming enfeebled till in 

 the Third Group we reach species smaller than in any other of 

 the Groups, and in which the sexual differences are slight or 

 almost wanting. 



B. ARMIGERUM, Macl. 



Only the male of this species has been described. I have seen 

 several examples, all from N. Queensland, but no Bolboceras has 

 come before my notice that seems likely to be its female. 



B. TRITUBERCULATUM, Bainb. 



The insect that Westwood figures as the female of this species 

 evidently belongs to the First Subgroup of Group ii., while the 

 male described by Bainbridge is a member of the Second Sub- 

 group. This I regard as impossible to be correct, and therefore 

 conclude that Westwood was mistaken in his identification. He 

 gives no description, nor any reason for his identification; and his 

 statement that the female was sent to him from Paris implies 

 that his name for it was not founded on circumstances of capture. 

 I have not seen any Bolboceras that appears likely to be that 

 which he figured as the female. 

 33 



