199 



tlic flotsam iui.l j(>tsniu inctliod as it has been called, — or 



is it a coiitiucntal area, at one time connected np to a conti- 

 nental area and sliariu.u' its fanna (and flora), but havinij be- 

 come separated at a ccvtain period, the fanna (and floi-a) thus 

 isolated havini>- evolved into what we now find ^ Most of the 

 bioloo-ists who have discussed this subject have incline(l to the 

 former opinion, but a few have lield the hitter. 



Prof. TT. A. Pilshi'v accounts for the presence of certain 

 primitive land shells and the absc^nce of certain more modern 

 groups by postnlatiuii- a continental Pacific area in late Palae- 

 ozoic or earlv jNIesozoic times. Tlie northern ])ortion of this 

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

 isolated first, the southern portion havinii' l)roken up at a some- 

 what later date, the present land shells Ixnni^- the representa- 

 tives of the faiimi of that period. 



The insects in no way sn]i]")ort this theory and in some 

 wavs o])pose it. If the insects represented that early era we 

 shonld be rich in Orthoptera and jSTenroptera, and especially 

 rich in Blattidae ; they shonld show some of the primitive 

 characters of the species of the Carlioniferons age, and among 

 the Hemiptera there shonld be traces of Protohemiptem and 

 Palaeoliemiptera belonging to the Permian age. If our Isl- 

 ands came nnder the inflnence of the Triassic insects we shonld 

 have forms of Chrysomelidae, Pnprestidae and other families 

 which are not represented. The snperfamily Fnlgoroidea, be- 

 sides the species of Delphacidae, is represented by only two 

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

 nous monotypic lolaniar We cannot consider these as primi- 

 tive forms or as representative of early Mesozoic times. 



The most remarkable thing about the Hawaiian fauna is 

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

 wide. The enormous family of Searabaeidae is entirely un- 

 represented ; Lncanidae 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 wliich I consider belong to this 

 genus. 



