144 Thomas 0. Sloane : 



Australian section of the tribe Helluonini, the Australian section 

 of the tribe Pseudomorphini, etc. The Carabidae are not suffi- 

 ciently carefully worked out and compared with those of other 

 regions for any work of value to be done yet. 



There is apparently no reason for entomologists to dissent from 

 the adoption of Spencer's three faunal sub-regions; they seem to 

 suit the Carabidae, though the order Coleoptera is so ancient that 

 its distribution might have been expected to accord with that of the 

 plants rather than with that of the mammalia. We will take a 

 brief glance at these three faunal sub-regions, and the districts into 

 which I divided them on entomological grounds in the year 1905. 



The Torresian has the richest fauna of any of the sub-regions of 

 Australia, and is largely stocked by Austro-Malayan types found 

 nowhere else on the continent. It is a tropical and sub-tropical 

 country with a variable climate, which in some places near the sea- 

 board has a high average rainfall, and a tropical flora, such as 

 accompanies a heavy rainfall where the soil is good; in other parts 

 rather dry, and with open forests; its rivers are numerous, though, 

 owing to there being no lofty mountains and the nearness of the 

 watershed to the coast, no such great rivers as might have been 

 expected are present. The Torresian and Eyrean sub-regions are 

 now fused together, with the arid climate of the Eyrean sub- 

 region as the chief obstacle to the complete intermixture of their 

 faunas. It is impossible to draw a definite line between these sub- 

 regions, unless empirically, as was done by Tate when he adopted 

 the line of twenty-five inches of mean rainfall as the boundary 

 between his Euronotian and Eremian botanical regions. It is rea- 

 sonable to expect that the hardy Eyrean fauna will have been able 

 to encroach into the more favoured Torresian region to a greater 

 extent than has the Torresian fauna into the Eyrean steppes T 

 though the comparative freedom from competition in the sparsely 

 inhabited Eyrean country may have been favourable to a widespread 

 range for some hardy Torresian forms. 



The districts proposed by me in the year 1905 for the division 

 of tlio continental part of the Torresian sub-region were three, as 

 under : — 



(1) West Torresian District. — Tli is was divided from the rest of 

 the sub-region by a line drawn north and south from near the 

 bottom of tli,' Gulf of Carpentaria. The typical insect fauna of the 

 West Torresian district will probably be found about the Daly 

 River, hut 1 know very little of the entomology of this district. The 

 strange genus Delimits of the tribe Pterostichini is peculiar to the 

 district. 



