Buacksurn—The Hawaiian Archipelago. 199 
vegetation larger than cactus, a dwarf acacia, and a stunted hibiscus, of which 
the last-named occurs occasionally and singly (though plentiful enough on the 
mountains), and the former two occur singly or in combination, in patches rarely 
exceeding a few acres in extent. The main part of the plains between the sea 
and the mountains consists of an expanse of undulating grass-covered country, 
with a few flowering plants scattered at intervals among the grass, a species of 
poppy, a solanum, and a “burr,” highly injurious to live stock, being the most 
conspicuous. These same plains, by means of irrigation from the mountains, are 
rapidly being brought under cultivation, and are found to yield exceedingly rich 
crops of sugar, rice, and other tropical products, but are almost devoid of interest 
to the coleopterist. They produce Adelocera modesta, M‘L. (in stems of cactus), 
Epitragus diremptus, Karsch.; Platydema obscurum, Sh.; Hopatrum seriatum, 
Boisd. ; and Heterophaga pandanicola, Esch. (the last four under stones), in some 
numbers ; and there are certain additional species (e. g. Cyllene crinicornis, Chev. ) 
apparently introduced with some of the numerous exotic trees and plants that are 
rapidly multiplying under the influence of irrigation. On the immediate fringe of 
the sea, and in salt-marshes, which extend here and there a mile or more inland, 
some half dozen other species are to be met with ; and under various circumstances 
of a probably accidental character, I have found on the plains some few others 
still, of which I know some to occur ordinarily in the mountain districts, and I 
suspect some to be of only very rare occurrence anywhere. 
The character and height of the mountain ranges varies greatly in different 
islands, though they all appear to agree in being of volcanic origin. On the 
islands forming the northern portion of the archipelago the ranges are from 
3000 to 5000 feet in altitude, and are of a somewhat peculiar form, con- 
sisting generally of an elongate and very strongly serrated ridge, or backbone, 
from either side of which, and at right angles to the main-line of the hills, 
numerous shorter ridges run out towards the plains. Between these latter are 
extremely deep valleys, usually supplied with a stream descending from the high 
land towards the sea. Many of the mountain ridges that separate one valley from 
another are so narrow as almost to resemble a knife-edge. I remember on one 
occasion making an attempt to reach, by one of these ‘“ knife-edges,” a particular 
summit that I wished to explore in the main south-eastern range of Oahu, and 
going on until the ridge became so narrow that trees growing upon it had to be 
climbed—up on one side and down on the other—because there was not room to 
go round them, I was at last stopped when very near the attainment of my 
purpose by a tree that I was unable to climb. At the northern end of each of the 
two southern islands—Maui and Hawaii—there is a single mountain range of the 
character just described, running more or less east and west, and with an altitude 
some 800 or 900 feet greater than that of the highest mountains in the northern 
part of the archipelago. 
TRANS. ROY. DUB. S0C., N.S. VOL. Ul. 2H 
