^66 Mr. R. C. L. Perkins — Introduction to 



With Ciridops in one direction the evolution o£ forms in 

 the first group ceases, while from Heter'orhynchus the second 

 proceeds through Pseudonestor to a series of thick-billed 

 birds quite unrepresented in the first. Consequently in dis- 

 cussing these remarkably analogous forms the six thick-billed 

 genera will here be excluded. Turning to the habits of the 

 birds of the remaining twelve genera^ eleven of these certainly 

 find all probably (the habits of Ciridops being little known) 

 contain at least some species accustomed to feed on nectar'^. 

 At the present time the main supply of this food is derived 

 from the Metrosideros — the well-known ^'Ohia-lehua^^ of 

 the natives^ and the predominant tree in the forests of all 

 the islands. Around the masses of red blossoms of these 

 trees may be seen at the proper season an assemblage of 

 various kinds of birds^ the scarlet " liwi ^^ {Vestiaria) and 

 the green or yellow ''Akialoa" {Hemiynathus) — both with 

 long curved beaks, — the crimson '' Apapane " {Himatione) 

 with moderate straight bill, and the green " Amakihi '' 

 {Chlorodrepanis) with moderate curved bill. The observer 

 wonders for what purpose such extraordinary developments 

 can have taken place. On the same flowers are numerous 

 bees peculiar to the islands, shortest of all short-tongued bees, 

 with a tongue one millimetre long, yet as well able to feed 

 on the nectar as the " Akialoa " with its tongue of two inches 



* Not that nectar is ever the sole food, though a most important source 

 of nutriment — so important to the aduhs of some species that at certain 

 seasons no individual shot contains any trace of insect food. Few 

 Hawaiian insects frequent flowers, and such as do, viz. one or two beetles 

 and the Hjanenoptera, are seldom if ever found in these birds' stomachs. 

 Nectar is imdoubtedly absolutely necessary to the existence of Himatione, 

 Chlorodrejxmis, Vestiaria, Hemicjnathus, and Drej)anis, as they are 

 constituted ; small moths, caterpillars, and spiders — their other food — 

 would certainly fail them at certain seasons. The honey-sucking Drepanids 

 and the Moho can be kept alive on nectar and sugar-cane juice. When a 

 species becomes purely insectivorous here, it shows extreme modification, 

 e. g. Fseiidonestm- and some Heterorhynchi, so that it may obtain special 

 insects inaccessible to other forms. In the introductory part of the 

 ' Fauna Hawaiiensis ' it will be necessary to give much space to com- 

 parisons between the birds, reptiles, molluscs, and insects, and between 

 the insects themselves, as well as to the Botany of the Islands. 



