86 



INSECTS OF SAMOA. 



3. Species restricted to Fiji and Samoa . , . . .11 



4. Provisionally endemic species ......... 28 



5. Species of general distribution in the Pacific ....... 4 



Considering these in turn, most of the holotropical species have probably 

 been introduced within historical times through the agency of man. Cimex 

 hemipterus has been carried by man himself, and Clerada apicicomis, which is 

 apparently an inquiline in the nests of various rodents, has probably been 

 carried by rats and mice. The widely distributed Oriental and Austro- Oriental 

 species are probably of very early origin, and have migrated from the west 

 either over a former land connection which existed during late Mesozoic times 

 between Papua and New Zealand, or later by the agency of winds and currents, 

 over a long j^eriod of time. The comparative richness of the Fijian and Samoan 

 fauna, and the number of closely allied endemic forms to which these austro- 

 oriental species have obviously given rise, strongly favours the existence of a 

 land connection, at least over the greater part of the distance, and migration 

 doubtless took place by both these methods. A considerable number of those 

 species which are restricted to Fiji and Samoa have been directly evolved from 

 the Austro-Oriental migrants, and must have originated in the Fijian group, 

 whence they have migrated to Samoa. That the endemic Samoan species 

 should appear to be so numerous is j^robably the result of insufficient knowledge 

 of the Fijian fauna, but it may be accounted for in part by the assumption that 

 a number of western migrants arrived by a course to the north or to the south 

 of Fiji. The occurrence of the common and widely distributed oriental Mezira 

 membmnacea in Samoa and its absence from Fiji favours this assumption. 



There is, too, some evidence from the distribution of the Hemiptera that 

 the fauna of both groups of islands received some migrants from the south, 

 probably from New Zealand. The Dysodiidae (Aradidae sens lat.), which are 

 typically forest insects, and reach their greatest development in South and 

 Central America, also occur very abundantly in New Zealand, although the 

 species are as yet undescribed. It is, indeed, quite probable that the New 

 Zealand Dysodiidae have been derived from Patagonia, and the fact that this 



land, Bismarck Archipelago, Solomon Is., New Hebrides, New Caledonia, and Loyalty Is. The 

 Philippines, except Palawan, are regarded as a distinct subregion. The Malaysian subregion 

 includes the Malay Peninsula south of 10° N., Sumatra, Java, Bali, Borneo, Palawan, and adjacent 

 islands. The Indo-Chinese subregion includes the southern slopes of the Himalayas, Burma, 

 Tenasserim, Assam, Siam, Cambodia, Cochin China, Laos, Annam, Tonkin, Southern China, 

 Hainan and Formosa. 



