6 
PACIFIC SCIENCE, VoL VIII, January, 1954 
mentous green and blue-green algae were also 
common. Diatoms of various species {Bactl- 
laria, etc.) and other one-celled forms such 
as Oocystis were numerically abundant in some 
stomachs but in bulk constituted a minor 
item. A few stomachs contained decomposed 
material, mostly from higher plants, which 
occurs as a light carpet over the sandy bottom 
of the stream. 
Insects ( 19.5 per cent) occurred in 19 of the 
46 stomachs. They consisted entirely of ter- 
restrial forms— mostly small ants, but also 
small beetles, springtails, leaf hoppers, and 
bugs, in order of decreasing percentage. The 
small ants, of common occurrence in the 
stomachs, must have fallen into the water by 
accident. The springtails were probably taken 
from the surface, where they hop about. Prob- 
ably the other insects were taken when they 
accidentally landed on the surface or when 
they were flying close to it. 
The crustaceans (5.8 per cent), occurring 
in 10 of the 46 stomachs, consisted primarily 
of fresh-water shrimp larvae, copepods, and 
amphipods. Foraminifera of several species 
(4.2 per cent) occurred in four out of six 
stomachs in one sample only. Similarly small 
spiders (0.4 per cent) occurred in two out of 
ten stomachs in one sample. Other food items 
(4.5 per cent) included unidentified eggs and 
the remains of a small tadpole {7), each of 
which occurred in one stomach only. 
Small (19-30 mm.) Fish from Salt Water 
The small aholehole from Ala Wai Canal 
(sample 6) have been grouped with those from 
salt water (samples 7 to 14) as the stomachs 
contained similar food items, although the 
chlorinity (13.7 p.p.m.) showed somewhat 
brackish conditions as compared with those 
along the seashore (18-19 p.p.m.). 
There is considerable variation in the pre- 
dominating food organism in the various 
samples. Molluscs were dominant in the sam- 
ple from Ala Wai Canal; Crustacea were dom- 
inant in one sample from Diamond Head 
(No. 7) and in those from Kuhio Beach, 
Kawailoa, and Lahilahi Point; insects were 
dominant in the other Diamond Head sample 
(No. 8) and in those from Sandy Beach and 
Waimea; foraminifera were dominant in the 
sample from Kualoa. There seems to be no 
general relationship between the type of dom- 
inating organism and the particular habitat 
(sandy shore, rocky shore, tide pool). In gen- 
eral, however, Crustacea and insects are much 
more abundant and algae much less abundant 
in the stomachs of small fish from salt water 
as compared with those from the fresh-water 
streams. The difference is interesting but not 
surprising— it probably reflects a difference in 
the relative availability of the three types of 
food rather than a difference in feeding habit. 
The food organisms found in the stomachs 
of small aholehole from salt (and brackish) 
water may be ranked in the following order 
of decreasing average abundance; Crustacea, 
insects, molluscs, foraminifera, algae, spiders, 
and annelids. 
Crustacea (48.1 per cent) of one kind or 
another occurred in 76 of the 81 stomachs. 
Table 2 shows the various groups arranged 
according to the average percentage by bulk 
and shows the number of stomachs in which 
they occurred. 
The copepods, including suborders Cyclo- 
poida, Harpacticoida, and Calanoida, were the 
most important item of the crustacean diet. 
They were followed by small amphipods 
(mostly Gammaridea) and isopods (including 
Tanaioida). Other crustacean forms occurred 
infrequently and formed but a small propo-r 
tion of the food. 
Insects (28.5 per cent) occurred in 54 of the 
81 stomachs. They occurred in the following 
decreasing order of abundance: midges, ants, 
wasps, roaches, beetles, bugs, thrips, and leaf 
hoppers. Midges and ants, together, com- 
prised the bulk of the insects. 
The midges, identified as Clunk littoralis by 
Wirth, occurred in the stomachs as larvae and 
pupae, but mostly as adults. They were found 
in all samples taken from tide pools and 
rocky shores but not in the sample from Ala 
