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thoughts these two genera might be supposed incapable of con- 
fusion, because according to their diagnoses (e.g., Lacordaire’s 
Gen. Col., vol. III.) Heteronychus should have organs of stridula- 
tion on the propygidium and unequal claws on the front tarsi of 
the male, while in Jsodon the organs of stridulation should 
be wanting and the male claws simple. But I find various 
combinations of these characters in species that are extremely 
closely allied even specifically, some with organs of stridulation 
having equal and others unequal claws in the male. 
The species that I am referring to agree in the following 
characters which in combination distinguish them from all other 
Australian Dynastides known to me,—viz., prothorax usually 
with well-marked sexual characters (in no instance known to me 
quite alike in the sexes), hind tibiz with very strong apical 
ciliz, basal joint of hind tarsi only feebly dilated at the apex, 
club of antenne not extraordinarily developed in the male, three 
external teeth (only) on the front tibia, one of the two apical 
spines of the hind tibize inserted more or less behind the base of 
the tarsus (in Vephrodopus, &c., it is differently placed), mentum 
of normal form (not as in Teinogenys, &c.), head not armed with 
a horn in either sex (at most a very small conical tubercle), 
clypeal suture well defined and not strongly angulate hindward 
in the middle (as it is in Dasygnathus, &c.), sides of clypeus 
sinuate, mandibles visible, labrum not prominent, front marginal 
furrow of prothorax not angulate hindward in middle (as it is 
in Adoryphorus, &c.). 
Fourteen Australian species presenting the above characters 
have been described (inclusive of Chetroplatys pecuarius, Reiche, 
which I have no doubt is an Jsodon). Of these three (viz., J. 
levicollis, Macl. and glabricollis, Macl. and H. vulgivagus, Oll.) 
appear to have been described without any knowledge of the 
male, and as the characters necessary to be known before their 
males can be identified are not given, I fear they must be treated 
as incapable of certain identification from description. Never- 
theless, I am fairly confident that I have not seen any of them. 
I. subcornutus, Fairm, is probably identical with pecuarius, 
Reiche, so that there are only ten species of which the male has 
been described. 
Four of these ten were described by Burmeister, but un- 
fortunately very briefly ; Australasie, Burm., happens to possess 
well-marked characters by which it can be identified, but the 
other three (all from W. Australia) present great difficulties. 
P. curtus, Burm., is described without. the mention of a single 
valuable character, unless it be “the second row of punctures 
from the suture (on the elytra) is the ieast regularly seriate.” I have 
