Vol. xxiv] ENTOMOLOGICAL NEWS 425 



lures of the islands, the general aspect of the flora and fauna, his 

 methods of collecting; the numher of species of insects, introduced, 

 immigrant and endemic; causes of extinction, distribution by natural 

 agencies, flightlessness ; origin of the fauna and species formation. This 

 general part of the introduction fills 59 pages, the remaining 155 being 

 given to special reviews of the Hymenoptera, Coleoptera, Lepidoptera, 

 Neuroptera, Embiidae, Termitidae, Psocidae, Odonata, Diptera, Hemip- 

 tera, Orthoptera, Thysanura, Collembola, Myriopoda, Arachnida, Mol- 

 lusca and Vermes. 



Notwithstanding the time devoted to these explorations, Dr. Perkins 

 emphasizes our very unequal knowledge of the fauna, the Diptera, for 

 example, being much behind the aculeate Hymenoptera. The total 

 number of Hawaiian species of insects known to him "is about 3325, but 

 of these only about 2740 can be considered as belonging to the natural 

 fauna." He thinks "It is possible that half the number of existing 

 species of insects have been collected, but this is by no means certain." 

 These "islands are much richer in species than has been supposed and 

 the scarcity of individuals of species exaggerated." (pp. xxxvii-xli). 



The interrelations of the plants and insects are very intimate, as is 

 shown by the fact that the .endemic species are chiefly to be found in 

 the true forest belt, which exists at elevations varying from 1200 to 

 3000 feet and whose two most characteristic members are the Koa 

 (Acacia koa) and Ohia (Mctrosiderus) trees. Much of the forest 

 has been destroyed, largely by cattle, and with it much of the endemic 

 fauna, but it is cheering to know that this loss is now being realized 

 and measures taken to prevent its becoming total (pp. xxvii, xxx). 



A very large number of Hawaiian insects have either one or both 

 pairs of wings functionless for flight, or entirely wanting. Examples 

 are known among the Lepidoptera, Diptera, Hymenoptera, Hemiptera, 

 Neuroptera, Orthoptera and Coleoptera. Dr. Perkins believes that all 

 these are "to be explained simply by 'disuse' " (pp. xlviii-lii). 



His view of the present Hawaiian fauna is that it "cannot be said 

 to belong to any of the great faunistic regions of the globe ; it contains 

 most important elements derived from the Oriental region, from the 

 Australian and from the Neotropical or at least from the warmer parts 

 of America, and it cannot be considered as even belonging chiefly to 

 any one of these regions. On present information it is decidedly not 

 Polynesian" (p. Ixx). It "is derived from waifs and strays from all 

 directions. At rare intervals from the Eocene till now chance immi- 

 grants have arrived. Some have been able to establish themselves, 

 many more probably, even after a landing has been effected, have 

 failed. Those that have been successful and have found congenial 

 conditions have often thriven amazingly, giving rise to hosts of de- 

 scendant species, as they have become adapted to, or become modified 

 by, diverse conditions" (p. Ix). Illustrations are the chalcid En[>cl- 



