52 



this case it is probably reliable. I have seen a good many 

 specimens of both sj^ecies and do not find the colour variable. 

 Other differences, unfortunately, do not lend themselves to 

 tabulation. II. gracilipes is evidently of narrower form than 

 copio^Ni and of more convex build, and its elytra have little 

 or no trace of granulation, their punctures, moreover, very 

 manifestly larger and less closely placed. The speci- 

 men from Kangaroo Island mentioned (in my notes on the 

 original description) as being of a somewhat ferruginous tone 

 of colour is in bad condition and evidently immature, and I 

 think there is no doubt that its dorsal surface not being black 

 is altogether due to its immaturity. 



H. iiicognitus, Blackb. This species is of narrow elon- 

 gate form like H. terrenas, Blackb., and differs from that 

 species, inter alia, by its larger size and the notably larger 

 and less closely placed punctures of its dorsal surface. The 

 character mentioned in the tabulation, viz., the straightness 

 of the lateral margin of its prothorax when viewed from the 

 side no doubt results from that segment being notably less nar- 

 rowed in front than is the same segment in the allied species 

 with the lateral margin sinuate when similarly viewed. 



//. severuA, Blackb. The type of this species is a female. 

 Since I described it I have received from the same locality 

 in Central Australia a male Heteronyx, which I regard, not 

 without hesitation, as specifically identical. It is larger than 

 the type (long., 5 1.) and differs from the tyjje by characters 

 that certainly are not usually sexual in Heteronyx, especially 

 the considerably finer punctures of its pronotum, the sides of 

 which are distinctly less strongly arched, and the lighter 

 colour of its dorsal surface (the males are usually the darker 

 in colour where there is a sexual colour difference). The 

 frons of this example is perpendicular in front as in the type, 

 but is not carinate above the declivity. The middle of each 

 of its basal three ventral segments bears two quite distinct 

 (but not sharply-defined) tubercles, and I find in the type 

 similar, though much feebler, unevenness on the corresponding 

 segments. It is the presence in both of this last-named very 

 peculiar character which hinders me from regarding them as 

 two species. It is so frequent a circumstance to find peculiar 

 characters in the insects of Central Australia that it seems 

 to me probable that this is a species in which sex has defined 

 itself in an unusiial way. 



H . cequalif!, Blackb. The presence of exceptional charac- 

 ters on the frons is too useful a character (in distinguishing 

 species') to be passed by, but unfortunately the species pre- 

 senting that character unmistakably are so linked on by at 

 least one intermediate form to those in which it is absent that 



