the Study of the Drepanidirlse. 563 



structure is probably greater in the beetles. If, however, we 

 were to reduce the hundred and thirty species oiProterhinus to 

 the number of species of the Drepanine birds, and particularly 

 if in doing so we were to eliminate the osculant forms, it is 

 manifest that the condition of the two groups would be 

 strikingly analogous. It is therefore in my opinion clear that, 

 making all allowance for the ease with which the one group 

 is studied, and the relatively great difficulty presented by the 

 other, there is a real and great difference between the Drepani- 

 didse and the Proterhinidse, and in fact between these birds 

 and most of the other extensive and peculiarly Hawaiian 

 groups of animals, and that the difference is due to the fact 

 that while in the birds there has been a keen competition 

 for existence between the various species and between the 

 individuals of each species, in the Proterhinidte there has 

 been little or none, because the food-supply of the latter, 

 consisting of dead wood, is in a forest-covei-ed country almost 

 unlimited. As will be hereafter noticed, there is good reason 

 to believe that the competition between the birds has been 

 much more keen in past times than during the more recent 

 periods of their existence. 



2. Origin of the Drepanididse doubtful. 

 If we compare the Drepauididse with other families of 

 birds, it is obvious that, considering the few species that 

 exist, they exhibit an unusual diversity of structure. As 

 a proof of this, it is only necessary to mention the fact that 

 competent ornithologists liave repeatedly assigned to different 

 families even those forms which without any possible doubt 

 belong to the same. This diversity of structure must have 

 required a vast time for its evolution, and the period at 

 which the ancestral Drepanid immigrated to the islands must 

 have been very remote indeed. Whether all the presently 

 existing species of this group have been evolved from one 

 original immigrant or from more we cannot say; but the 

 former view is probably the more correct, although two 

 ancestral immigrants might be admitted. 



That the islands were originally stocked by numervus 



