686 REVISION OF THE AMYCTERIDES, iv., 



9. More robust than male. Ventral surface convex. 



This genus was proposed, by Macleay, for what must be 

 regarded, on the whole, as a very homogeneous group of species, 

 " the greater number [of which], and all the more typical ones, 

 are inhabitants of the great basin of the interior, which has its 

 outlet in the colony of South Australia." Macleay, in his 

 remarks on the genus, says — "the main feature of the genus is 

 the broad flat rostrum, with a central ridge extending in most 

 cases to the vertex." While this is true of the typical species, 

 there are cases, however, where the centre of the rostrum cannot 

 strictly be called carinate. As there are, at present, included in 

 'Talaui'inus, many species in which the internal rostral ridges 

 are obsolete, confusion of the genera may arise, and, in the past, 

 has arisen. It seems to me, however, after examining large 

 series of specimens, that, in cases where doubt might arise, the 

 obvious affinities of the species are sufficient to indicate their 

 true position; and, although the median area may not be dis- 

 tinctly carinate, it is generally raised, or convex, and never de- 

 pressed, or sulciform, as it is so generally in Talaurinus. 



The lateral, or, more correctly, the sublateral, sulci are broad, 

 and extend for the greater part of the rostrum, generally with a 

 deeper basal fovea; in some species, however, through the sub- 

 triangular elevation of the median area, the sulci are practically 

 limited to these basal fovete. Internal ridges are never present, 

 though the edges of the median area, being often marked by 

 vittse, may give the appearance of internal ridges. The scrobes 

 and the relative position of the eyes do not exhibit any great 

 degree of variation. The prothorax is generally more or less 

 ampliate on the sides, and the ocular lobes are, on the whole, 

 fairly strongly marked; the granules or tubercles on the disc 

 vary, and are not always constant in shape or size in the same 

 species. 



The elytra do not present the wide divergence in sculpture so 

 characteristic of Talaurinus; practically all the species may be 

 described as tuberculate. The tuberculation, however, is variable, 

 the tubercles in some species being small and granuliform; in 

 others, showing a tendency to coalesce to form costse; in all cases, 



