Distribution of Moths of the Sub-family Bistonincs. 193 



Brazilo-Africano-Malagasco- Australian continent, and likewise 

 that across the Pacific were yet in their prime. Once again we 

 are thrown far back through Tertiary times to the mists of the 

 Secondary Epoch. Nevertheless, the universal occurrence of 

 fossil marsupials tells us in no uncertain voice that the last link 

 to vanish was the old Eocene connexion with Eastern Asia. 



We have thus a ready explanation of the Tropical and 

 Sub-tropical endemic forms, but in it there is nothing explica- 

 tory of the thin — very thin — veneer of Palaearctic forms found 

 both in Australia and New Zealand. It is very easy to say 

 that, if such exist, the Palaearctic representatives are outliers 

 and the Australian the original stock. Such is undoubtedly 

 the case with very many groups as was to be expected, in 

 view of the small dilution and the extreme age of the Australian 

 and New Zealand Flora and Fauna, contrasted with the 

 mixed association of sturdy virile forms which have effectually 

 stamped out and replaced the majority of the Secondary and 

 early Eocene genera, families and even orders in other zoo- 

 geographical regions. Vastly different is the case here ; from 

 its attachment to the Holarctic Realm, as betrayed by all of 

 its present stations and migrations, and from its emphatically 

 temperate inclinations, the Bistonine Subfamily must be of 

 Boreal origin, and, to use a homely but expressive colloquialism, 

 here ' the boot is on the other leg.' It is the Australian insect, 

 Lophodes sinistraria, which is the outlier. Nothing proclaims 

 this more strongly than the huge spine on the vesica of the 

 male genitalia and the close approach of the whole genital and 

 antennal structures to those of the early transition forms 

 between the Boarmioid and Non-Boarmioid Bistonince. 



Still, this problem of its eccentric distribution must have a 

 solution, and this solution it is our business to find. ' It might 

 be put forward that, in the consideration of the non-endemic 

 temperate element of Australia and New Zealand, we are face 

 to face with relics of the Flora and Fauna of the old Antarctic 

 Continent rather than with organisms of northern origin, and, 

 at first sight, indeed, some countenance is apparently given 

 to such an opinion by the appearance of Alpine genera like 

 Erelia (as Erebia patagonica) in Tierra del Fuego, and, in 

 its modified guise of Perenodaimon [Erebia) brdleri and P. 

 pluio, in New Zealand. But it was said advisedly ' at first 

 sight,' for Erebia is again a purely Palaearctic genus, and it 

 attains a tremendous development in that region. Its presence 

 in Patagonia and Tierra del Fuego, as well as that of our 

 familiar little Durham speciahty the Birds-eye Primrose 

 {Primula farinosa) admit of the easy explanation that both 

 passed down the lofty and continuous Rocky Mountains and 

 Andes, for both are familiar objects in suitable portions of the 

 Canadian Subregion. Perenodaimon, in New Zealand, belongs 



T918Junel. 



