199 



— the flotsam and jetsam method as it has been called, — or 

 is it a continental area, at one time connected up to a conti- 

 nental area and sharing its fauna (and flora), hnt having be- 

 come separated at a certain period, the fanna (and flora) thus 

 isolated having evolved into what we now find ? IMost of the 

 biologists who have discussed this subject have inclined to the 

 former opinion, but a few have held the latter. 



Prof. IT. A. rilsl)r_v accounts for the presence of certain 

 primitive land shells and the absence of certain more modern 

 groups by postulating a continental Pacific area in late Palae- 

 ozoic or early ]\Iesozoic times. The northern portion of this 

 area, of which the Hawaiian Islands are the remnants, became 

 isolated first, the southern portion having broken up at a some- 

 what later date, the present land shells being the representa- 

 tives of the fauna of that period. 



The insects in no way support this theory and in some 

 ways oppose it. If the insects represented that early era we 

 should be rich in Orthoptera and Keuroptera, and especially 

 rich in Blattidae; they should show some of the primitive 

 characters of the species of the Carboniferous age, and among 

 the Hemiptera there should be traces of Protohemiptera and 

 Palaeohemiptetu belonging to the Permian age. If our Isl- 

 ands came under the influence of the Triassic insects we should 

 have forms of Chrysomelidae, Buprestidae and other families 

 w^hich are not represented. The superfamily Fulgoroidea, be- 

 sides the species of Delphaeidae, is represented by only two 

 genera of Cixiidae, the world-wide Oliarus and the autochtho- 

 nous monotypic lolania* We cannot consider these as primi- 

 tive forms or as representative of early Mesozoic times. 



The miost remarkable thing about the Hawaiian fauna is 

 the absence of many large groups, some of which are world- 

 wide. The enormous family of Scarabaeidae is entirely un- 

 represented ; Lucanidae is only represented by a single autoch- 

 thonous genus with one or two closely related species ; Chryso- 

 melidae is not represented by any species we can consider na- 

 tive. In these cases we can understand that the feeding habits 

 of the young and the poor flight of the adult would prevent 

 them traveling any long distance over sea. Similar cases can 

 be drawn from each of the large orders of insects, as Dr. Per- 



*I have specimens from Fiji which I consider belong to this 

 genus. 



