CHAP. XIII. ] THE AUSTRALIAN REGION. 421 
the former are almost always the largest. As examples may be 
mentioned, Ornithoptera priamus and O. helena of the Moluccas, 
both larger than the varieties (or species) of Papua; Papilio 
ulysses and deiphobus of Amboyna, usually larger than their 
allies in New Guinea; Hestia idea, the largest specizs of the 
genus; Diadema pandarus and Charaxes ewryalus, both larger 
than any other species of the same genera in the whole archi- 
pelago. Itis to be noted also, that in the Moluccas, the very 
largest specimens or races seem always to come from the small 
island of Amboyna; even those of Ceram, the much larger island 
to which it is a satellite, being almost always of less dimensions. 
Among Coleoptera, the Moluccas produce Huchirus longimanus, 
one of the largest and most remarkable of the Lamellicornes ; 
Sphingnotus dunningi, the largest of the Austro-Malayan Tme- 
sisternine ; a Sphenura, the largest and handsomest of an exten- 
sive genus; an unusually large Schizorhina (Cetoniide) ; and 
some of the most remarkable and longest-horned Anthotribide. 
Even in birds the same law may be seen at work,—in the Tany- 
suptera nais of Ceram, which has a larger tail than any other in 
the genus ; in Centropus goliath of Gilolo, being the largest and 
longest-tailed species; in Hydrornis maximus of Gilolo, the 
largest and perhaps the most elegantly and conspicuously 
coloured of all the Pittide; in Platycercus amboinensis, being 
pre-eminent in its ample blue tail ; inthe two Moluccan lories 
and Hos rubra, being more conspicuously red than the allied New 
Guinea species ; and in Megapodius wallacei of Bouru, being the 
only species of the genus conspicuously marked and banded. 
All these examples, of larger size, of longer tails or other 
appendages, and of more conspicuous colouring, are probably 
indications of a less severe struggle for existence in these islands 
than in the larger tract of New Guinea, with a more abundant 
and more varied fauna; and this may apply even to the smaller 
islands, as compared with the larger in the immediate vicinity. 
The limited number of forms in the small islands compared 
with a similar area in the parent land, implies, perhaps, less 
competition and less danger; and thus allows, where all other 
conditions are favourable, an unchecked and continuous de- 
