838 AUSTRALIAN COLEOPTERA, WITH DESCRIPTIONS OF NEW SPECIES, 



touch the apex of the fourth segment in the middle. In what I 

 regard as the female there is a very small sixth segment bearing 

 two shoi-t apical setfe ; in the other sex (as I take it to be) this 

 segment is a little larger and without apical setse, but these 

 differences may be accidental. 



This species appears to be somewhat variable ; I possess speci- 

 mens differing from the type described in having the puncturation 

 of the prothorax considerably obliterated on the middle of the 

 disc, and the angulate appearance of the sides of the same segment 

 only feeble. 



Probably allied to the Queensland H. acutipennis, Fairm., but 

 differing from it considerably in the sculpture of the prothorax, 

 in having the part of the head behind the clypeal suture 

 punctured similarly to the prothorax, and in having the eiytral 

 striae not " scarcely growing obsolete at the apex," but altogether 

 disappearing before the apex. From H. luridipennis, Macl., it 

 seems to differ in having the thorax transverse with its angles 

 not acute. 



Placed beside the European H. angustata, Sturm, the general 

 form is shorter and broader, the prothorax is evidently more 

 transverse with its surface rendered much more uneven by 

 transverse and longitudinal depressions, the eiytral striae much 

 more obsolete behind, and the elytra separately pointed instead of 

 being rounded off. The puncturation does not differ much. 



Near Adelaide ; in the river Torrens. 



N.B. — In the South Australian Museum there is a specimen of 

 Hydrcena, taken in Victoria by Mr. Tepper, which I refer with 

 some doubt to this species. The elytra appear a little more 

 strongly striated in front, and at the apex are much less acute, 

 being separately rounded rather than distinctly acuminate. The 

 hind tibife, moreover, are bisinuate on their inner edge ; this 

 latter may be merely a sexual character. In all other respects 

 the two insects seem to be quite identical. 



