■ INTRODUCTION . xvii 



covering some 1800 miles. These small islands have been to some considerable extent 

 explored in search of birds, but very little is known of their other inhabitants. 



Laysan, a low island, is remarkable for its Drepanid birds and various Noctuid 

 moths, both clearly allied to species inhabiting the main islands of the group, while 

 Midway also has produced a few insects allied to those on the larger islands. Both 

 these islands, however, have yielded species with no allies on the main group, 

 e.g. Laysan the small bird Taiare faniiliaris and Midway a species of true Chrysopa 

 in Neuroptera and a Noctuid moth of the genus Prodenia. Laysan has for a number 

 of years been worked for its guano deposits, and, more recently, a cable station has 

 been made on Midway, so it is probable that both these islands are now, or soon 

 will be, overrun with imported insects. 



Niihoa or Bird island rising to an elevation of about 900 ft. is the most lofty 

 of the smaller islands, and was visited by an excursion party some 25 years ago. 

 Its geology was studied by Dr S. E. Bishop, but its zoology was neglected. No 

 doubt it contained some much more interesting animals than the countless sea-birds 

 that were noticed. The vegetation being dry was carelessly set on fire, and probably 

 the most interesting part of the fauna was destroyed. It is known that there then 

 existed a thick-billed Passerine bird, probably allied to Telespiza of Laysan. 



Oahu, Plate V. Of the forest-bearing islands the one whose fauna has been 

 most studied is Oahu. Here more than half a century ago Deppe and Townsend 

 made an extensive collection of the native birds, at a time when these were evidently 

 abundant, more numerous, as they state, than on the more northern island of Kauai. 

 In more recent times the relative abundance of birds on these two islands has entirely 

 changed, no doubt owing to the chief port and settlement of the group having become 

 established at Honolulu on Oahu, and the greater and earlier interference with its 

 natural conditions, that were brought about thereby. Blackburn's well-known re- 

 searches on the insect fauna were mainly carried out on Oahu during the six years 

 of his residence at Honolulu. Similarly the great variety of its land molluscs and 

 the beauty of many of these have induced many residents in Honolulu to become 

 collectors, either temporarily or continuously. 



The area of Oahu is 598 square miles and for its size there is reason to suppose 

 that it is or has been one of the richest of the group in its fauna. It is rather more 

 than 70 miles from Kauai, at their nearest points, and 25 from Molokai. Like Maui 

 and Molokai it is formed of a fusion of two islands. Of quadrangular shape the 

 west side is occupied by the Waianae range, of much greater age than the longer 

 Eastern or Koolau range, and, doubtless, existing as a distinct island long before 

 the latter emerged from beneath the sea. The highest peak of the Waianae range 

 is Kaala (4030 ft.). There are several large and deep valleys each containing a 

 stream of water on its western side, and on the eastern side it is also much eroded 

 into deep gulches and valleys. On this side its lower slopes are overlaid by the 



F. H. I. c 



