22 
Psyche 
[March 
tains everywhere, but rarely at low altitudes in the tropics. The few- 
ness of flightless Carabidae at low altitudes in New Guinea is an 
example. I have discussed this subject, with other examples, else- 
where (1943). 
Finally there is a partial correlation between size of Carabidae and 
climate. Very large Carabidae (over 1 to 2^/2 inches long) are numer- 
ous in the forests of warm temperate to tropical eastern Australia but 
relatively few or absent in both cool temperate Tasmania and wholly 
tropical New Guinea. If Catadromus tenebrioid.es (ol.) is introduced, 
as I think it is, the largest carabids in New Guinea are hardly an inch 
long and few are that large. I suspect that this correlation has a 
complex ecological basis which may include direct action of physiologi- 
cal factors, correlation of size with state of wings and flight, and 
competition with other insects. Of insects that might compete with 
carabids, ants are most obvious. I have suggested (1943, p. 42, Fig. 4) 
that ants may take the place of most flightless geophile Carabidae 
especially in the lowland tropics. 
Geographical History of Carabidae 
Carabidae, like other old, complex groups of animals (mammals 
etc.), have presumably had complex geographical histories, with suc- 
cessive dominant groups evolving, spreading over the world, and 
replacing older groups. The present distribution of Carabidae in 
the Australian Region may reflect this. Some localized tribes that 
are now confined to the cool south temperate zone may be remnants 
of an ancient fauna (see Darlington i960 for further discussion of 
some of these groups). Pterostichini, now dominant in most of Aus- 
tralia, may be more recent and may be replacing more ancient Carabi- 
dae. And Agonini may be still more recent, now dominant in New 
Guinea (and in the whole tropical Asiatic- Australian area), and 
spreading to Australia. 
Pterostichini and Agonini tend, as dominant tribes, to be com- 
plementary over the world as a whole. I have discussed this before 
(1956, pp. 1-3), but what I said then is worth repeating briefly now, 
with counts of species brought up to date. Both tribes are cosmopoli- 
tan, but unevenly so. In some parts of the world they occur in nearly 
equal numbers, in others, one tribe or the other is overwhelmingly 
dominant. The tribes tend to be complementary within the Australian 
Region, as already indicated. In Australia itself (with Tasmania) 
Pterostichini are dominant, with more than 350 known species against 
probably less than 20 species of Agonini, a ratio of nearly 40/1. But 
