IN TROD UC TION Ixxi 



The antiquity of the group must be extremely great. The possibiHty of an ancient 

 continent, even were it probable geologically, cannot for a moment be entertained by 

 the student of the whole fauna. We should require connection with or approximation 

 to the Oriental region, just as much as to the American continent and Australia. 

 There is no possibility of an ancient land connection having existed even between the 

 islands of the group themselves during the period in which they became colonized by 

 the progenitors of the present fauna. Some groups of insects, considered by themselves, 

 may show nothing actually opposed to this supposition, but others prove it to be 

 quite untenable. Of those who have worked on the material collected by me, I think 

 Lord Walsingham alone has favoured the idea of an ancient continuous land area. But 

 the study of these winged insects is not favourable for forming a conclusion on this 

 point. If we consider other of those that are evidently amongst the most ancient 

 inhabitants of the islands, we see the impossibility of such a theory. The absence of 

 Achatinella, s.L, from Kauai at one end of the group, and its almost total absence from 

 the great forests of Hawaii at the other (where only a single type represented by two 

 or three species is known), the presence of Carelia on Niihau (until recently) and 

 Kauai, but absent from all the other islands, may be noticed in the Mollusca. The 

 development of highly specialized endemic genera of Finch-like Drepanididae on Hawaii 

 and their entire absence from the other islands, except for a vagrant, ubiquitous form 

 {Psittacirostra) and one other {Pseudouestor) peculiar to Maui, the island nearest to 

 Hawaii, are noteworthy in the birds. The vast development of species of the endemic 

 flightless genera of Carabidae, allied to Cyclothorax, on Maui and its neighbouring 

 islands, their poverty in Oahu, and total absence from Kauai, may be cited in insects. 

 The lack of a single individual of great groups of animals containing countless species, 

 ubiquitous in every land, except very remote Oceanic islands, not only forbids the idea 

 of any continental area, but leads us to conclude that the islands have never been even 

 in past ages much less isolated from other lands than they now are. We have elsewhere 

 shown the difficulty that creatures, whose ancestors must have traversed thousands ol 

 miles to reach the islands, have had in spreading throughout the group, and even after 

 ages many have not achieved this. This is certainly more or less attributable to that 

 sluggishness which appears so generally to overtake the descendants of animals that 

 reach the sparsely inhabited forests of these remote islands. On Hawaii we observe 

 even in birds so powerful as the native buzzard and the crow, an unreasonable restriction 

 to that one island, and even to parts of that island. In the Hawaiian islands and else- 

 where, the loss of flight of so many insects and less frequently of birds follows disuse. 

 Given sufficient time (and the extraordinary antiquity of the archipelago is manifest) aU the 

 phenomena of the fauna are readily explicable on the supposition that a comparatively 

 small number of immigrant species have at various periods been able to reach and 

 establish themselves in the islands. With a disinclination to wander, as seen in the 

 case of the crow and buzzard, above mentioned, it has often taken the descendants of 



