450 
Notes on Hawaiian Aphidae, With a List of Food Plants 
(Homoptera). 
BY Pe EL VB RAKES 
(Presented at the meeting of December 6, 1923.) 
The number of aphid species occurring in Hawaii is not 
great, but some of them are of considerable economic impor- 
tance, among which should be mentioned Aphis sacchari, A. 
maidis, A. gossypu, and A. medicaginis. Some, such as Macro- 
siphum solanifolu, which are important pests elsewhere, confine 
themselves almost exclusively to weeds and are, therefore, negli- 
gible here in an economic sense. The thirty-seven species now 
known from the Islands are apparently all introduced, and there 
is no absolute certainty that there was any aphid fauna at all in 
the Islands before the establishment of commercial relations with 
the outside world in the early part of the nineteenth century. 
The purpose of these notes 1s primarily ecological, or to pro- 
vide a working list of the species, together with their food plants. 
I have, therefore, not attempted to describe any of the species 
which are apparently new, but in the case of species of uncer- 
tain identity | have found it desirable to place on record a few 
simple characters by which they may be distinguished from their 
congeners present in the Islands. The classification employed is 
imamly that of Mr. A. © Baker (U. S2 Dept. Actics bull 
No. 826, 1920), but with some modifications where Mr. Baker’s 
treatment seems somewhat too rigid. My thanks are due to Mr. 
Baker for the identification of several species. 
SUBFAMILY APHINAE. 
TRIBE LACHNINI. 
1. Lachnus tujafilinus (Del Guercio). 
This species has been discovered recently by Mr. Ehrhorn, 
who found apterous colonies on Thuya occidentalis L. in Manoa 
Valley, Oahu, at the last of January and during February, 1924. 
On account of the peculiar marking of the apterous form of this 
species, I believe that there is no doubt about the identification. 

Proce. Haw. Ent. Soc., V, No. 3, December, 1924. 
