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Multiplying generation after generation throughout the season, 
and each new generation, under favorable circumstances, soon itself 
commencing to multiply, it is easy for a species ordinarily quite 
insignificant suddenly to burst its bounds, if conditions become tem- 
porarily never so little favorable, and to appear in overwhelming 
numbers, inflicting extraordinary damage. It is therefore unques- 
tionably well that strawberry growers should know that their plants 
are subject to such attacks; and they should likewise unquestiona- 
bly be able to recognize these insects when they occur in their 
fields, and should be made acquainted with the measures needed to 
restrain them, provided any such sudden and destructive outbreak 
takes place. 
LITERATURE. 
The first mention of the occurrence of any plant-louse on the 
strawberry in the United States, which has come to my knowledge, 
is contained in the Rural World of December, 1875, where Prof. 
Riley briefly characterizes a variety of Siphonophora fragarie, Koch, 
under the name of immaculata, and reports its occurrence in West- 
ern Missouri. Next, in the second bulletin of the Illinois State Labo- 
ratory of Natural History, published in 1877, Dr. Cyrus Thomas, 
then State Entomologist of Illinois, in a list of the plant-lice of the 
State belonging to the tribe Aphidini, merely mentions a green 
plant-louse, upon the strawberry, which he assigns to the above 
species. In his report as State Entomologist, for 1879, Dr. Thomas 
briefly treats this plant-louse, translating the original description of 
Koch, and adding, ‘‘This species feeds upon the strawberry plant, 
especially the under sides of the leaves and the stalks of the unripe 
fruit. A species which I presume is identical with this has been 
occasionally observed on strawberry plants in this State, but so far 
I have been unable to procure specimens. In 1675, Prof. Riley 
received from Mr, W. W. Hopkins, of Kansas City, specimens of a 
plant-louse which was injuring his strawberry plants. From a copy 
of his notes on these specimens, which was very kindly sent me, I 
learn that they differ from Koch’s description in wanting the spots 
on the sides of the abdomen in the winged female, and in the head 
of the wingless female being yellow; yet he decides without serious 
doubt, that they belong to Koch’s species. He names this variety 
ammaculata. 
The next reference to a strawberry plant-louse is that contaimed 
in a paper* by Prof. Riley and Mr. Monell, published in the same 
year, in which the latter indicates the peculiarities of the variety 
wmmaculata, and expresses the opinion that it is possibly a distinet 
species. 
*Notes on the Aphidide of the United States, with Descriptions of Species Occurring 
West of the Mississippi. Bulletin of the United States Geological and Geographical Sur- 
vey of the Territories, 1879, Volume V, Number 1. 
