195 



H. dimidiatus, Er., and its allies. The species forming 

 the aggregate A in my tabulation of characters in this Group 

 are very distinct from all other Ileteronyces known to me, not 

 only by the combination of characters indicated in the tabu- 

 lation, but also by the presence of an unusually well-marked 

 difference between the sexes in respect of the front claws, the 

 basal piece of those claws bearing on the inner margin in the 

 male a laminiform process of more or less quadrate form, 

 which, however, is feebly represented in the female also (the 

 basal piece in the female being of a conspicuously compressed 

 form). The males, moreover (in all the species of which I 

 know the sexes with certainty) differ from the females in the 

 presence of dark colouring on the basal part of the elytra. 

 In this aggregate must be placed a species represented by a 

 female example in the Macleay Museum ticketed with one of 

 Mr. W. S. Macleay 's labels bearing the name "Cotidia aus- 

 tralis, Gory," under which name there is a quasi-description 

 in Boisduval's memoir in the "Voyage de l'Austrolabe." The 

 name "australis," however, had been used previously by 

 Guerin for a Heteronyx from Tasmania which could not be 

 identified or even referred to one of my Groups without exam- 

 ination of the type, as there is no reference to the labrum in 

 the description ; but there is nothing in the brief description 

 inconsistent with its being a member of this present aggregate. 

 The size given by Guerin (long., 11 mm.), nevertheless, points 

 to its probably belonging to some other aggregate (probably 

 Group IV.), and the locality renders it improbable that in 

 any case Cotidia australis is identical with it. Heteronyx 

 (Cotidia) australis, Gory (apparently a MS. name adopted 

 by Boisd.) must, therefore, be regarded as a nom. pros-occ. I 

 described the same species (Proc. Linn. Soc, N.S.W., 1889, 

 p. 672) under the name fallax, which, consequently, must 

 stand as its name. The species of this aggregate are for the 

 most part easy of identification, inter se, as will be seen by 

 a reference to the tabulation. There are two of them, how- 

 ever, about which I am in some difficulty (II. dimidiatus, Er., 

 and //. jubatus, Blackb.), to the extent that I am not quite 

 certain regarding their females, inasmuch as I have not seen 

 a female likely to be dimidiatus from the original locality 

 (Tasmania), nor one from any other locality identical with 

 any locality from which I have the male of dimidiatus. I 

 have before me, however, a female from the Jenolan Cave 

 district, and another from Armidale, which I cannot separate 

 from male dimidiatus by any character not likely to be sexual. 

 The males of dimidiatus, Er., and of jubatus, Blackb., are 

 quite easy to distinguish from each other, the former being of 

 narrow elongate form — the prothorax especially narrow, its 



