1322 
REVISION OF THE GENUS HETERONYX, 
the limits of the genus, — and then concerning the characters that 
appear to me most reliable for distinguishing and sub-dividing 
the numerous species that are attributable to it. 
As originally chai'acterized byM. Guerin-Meneville, the genuswas 
accommodated to the reception of the single species known to that 
author, but the discovery of additional species soon made it clear 
that there are many insects evidently congeneric with H. Australis, 
for which a place must be found in Heteronyx, by the removal 
from the category of “ generic characters ” of some characters that 
had been so regarded. M. Lacordaire (Gen. Col. III. 231), conse- 
quently I’e-characterized the genus, but in a manner that will not 
stand as absolutely satisfactory when a large collection of types is 
examined, for a rigid adherence to his diagnosis of the anterior 
tibim would exclude species that (so far at least as my observation 
goes), present no other distinctive character either stnictural or 
superficial, while a similar application of his diagnosis of the claws 
of the tarsi would admit species difiering in other important 
respects from the typical form. 
Among the genera found in Australia then, possessing the 
characters that would place them (in M. Lacordaire’s system) in 
the “groupe Ueteronycides ,” — it appears to me that Heteronyx 
should contain only the species presenting the following charac- 
ters ; — “ elytra not abnormally short (as in Liparetrus), antennm 
of eight or nine joints, claws not simple,” and I have not seen any 
possessing these characters that I should be disposed to exclude ; 
I regard the last-mentioned of these characters as the most essen- 
tial one. 
The following names are, or have been regarded as, more or less 
.synonymic with Heteronyx. 
Silopa, Er. (Wiegm. Arch. 1842, I. p. 161). This genus was 
characterized probably on Heteronyx Australis, Guer., — certainly 
on a true Heteronyx, — and is an absolute synonym. 
Omaloplia, Steph. This is a non-Australian genus to which an 
Australian species (of Caulohius probably) was erroneously 
referred by MM. Hombron and Jacquinot. 
