4 FAUNA HAWAIIENSIS 



be remarked, that in the case of two of its three species which are found also on other 

 islands, the Kauai form is by no means identical with that occurring elsewhere, but 

 exhibits well-marked variation. Hawaii with far the largest area of any of the islands, 

 has the greatest number of species, and ranks next to Kauai in the proportion of those 

 peculiar to it. Maui with the second highest total of species has a much smaller 

 proportion of peculiar ones than Oahu. In general the more remote is a given island 

 from its neighbours the greater is the peculiarity of its fauna. The fact that Hawaii 

 and Kauai are placed at either end of the chain of islands would tend to increase the 

 endemic at the expense of the total number of their species, since they give and receive 

 emigrants in one direction only. It is true that the island of Niihau lies to the west 

 of Kauai, but it is a small and unimportant island with no considerable mountains, which 

 can never have possessed more than a scanty fauna, and being now a pasturage for 

 sheep was not visited by me. The Aculeata of the three adjacent islands Maui, 

 Molokai and Lanai are much more nearly related, and a large number of species are 

 common either to two, or to all of them. The mountains of West Maui yield some of 

 the species which otherwise are quite peculiar to Molokai. That Maui surpasses 

 Molokai in the number and in the peculiarity of its species is due to the much greater 

 size and much more varied conditions of the former island. Its two widely separated 

 mountain masses each yielding peculiar species, the great elevation of Haleakala, of 

 which the region above the forest-belt has a special fauna, and the extensive low 

 sandhills, dividing its eastern and western mountains, and favourable for Hymenoptera, 

 give it a great advantage. Hawaii, as might be expected from the extreme difference 

 in climate between the leeward and windward sides, and the very great height of its 

 mountains, is very rich in species, and its position is favourable for a high percentage 

 of forms peculiar to it. Oahu has the advantage of two separate mountain-ranges, 

 each with some peculiar species, but the mountains are only of moderate height. 

 Only two of its species are the same as those of Kauai, but it has seven identical 

 with those of the less distant island of Molokai. Apparently not a single one of 

 the species tabulated above extends its range over the whole group, although two 

 or three are found on all the islands from Oahu to Hawaii. 



With regard to the affinities of the endemic Hawaiian species, with those of other 

 countries I think, in the present state of our knowledge, that there is little to be 

 said. F. Smith expressed the opinion that they were most nearly related to the North 

 American aculeates. Probably he based this opinion partly on the occurrence of certain 

 well-known American species (of Xylocopa, Polistes, Pelopceus), and partly on the state- 

 ment of de Saussure that certain of the Odynerus belonged to groups found in 

 N. America. As I have mentioned above those American species that are known 

 to occur also in the islands, have certainly been introduced by man, and therefore 

 cannot be taken into account in deciding the affinities of the fauna. De Saussure's 

 opinion on the Odyneri is open to suspicion, because he assigns the Hawaiian species 



