590 REVISIONAL NOTES ON AUSTRALIAN CARABID.E, V., 



Genus Helluapterus, n.gen. 



Convex, apterous. Head large: neck wide; eyes prominent; 

 postocular parts of orbits small, oblique to neck. Antennte stout, 

 elongate, compressed: four basal joints cylindrical, sparsely setose. 

 Labrum large, depressed, widely rounded at apex, sparingly 

 punctate; one sensitive seta on each side near anterior angles. 

 Mentum deeply emarginate: bottom of sinus forming a short 

 wide prominence in middle : lobes triangular. Ligula wide, 

 roundly prominent at apex : a median double row of widely 

 placed setigerous punctures. Palpi : labial stout; penultimate 

 joint thick, incrassate; apical joint claviform, a little shorter 

 than penultimate; maxillary with penultimate joint short, two- 

 thirds the length of apical: this larger and stouter than apical 

 joint of labial. Maxillse with inner lobe stout, sharply hooked 

 at apex: inner margin strongly triangularly angulate in middle, 

 beset with separate spiniform setae on anterior part. Prothorax 

 transverse, strongly ampliate at widest part, strongly sinuate- 

 angustate to base; base truncate. Elytra truncate-oval, convex; 

 interstices 3, 5, and 7 costate; inflexed margins wider and more 

 sparsely setose than usual in the tribe. Metasternal episterna 

 shorter than usual (4x2-5 mm.). Tarsi with penultimate joint 

 narrow, simple; anterior with second and third joints biseriately 

 squamosa beneath in ^. 



Habits terrestrial. 



This genus differs from Helluo by the longer basal joints of 

 antennae (fourth much longer and less densely pubescent) ; 

 mentum with lobes shorter, median tooth much shorter and 

 wider; maxillae with inner lobe far less hairy, and with a very 

 strong triangular prominence on middle of inner side; inflexed 

 margins of elytra wider and less setose; joints of tarsi longer, etc. 

 From Gigadema, it differs by facies (elytra convex); absence of 

 wings; short metasternal episterna, etc. It is evidently derived 

 from the primitive central stem of the tribe, from which Helluo, 

 ffelluarchiis, and Gigadema also come. 



Helluapterus niger, n.sp. 



Robust, oval, convex, sparsely punctate. Elytra truncate- 

 oval, punctate-striate; third, fifth, and seventh interstices raised 

 above others. Black. 



