195 
It would be impossible to curtail this report to any large ime "ees 
as Professor Riley has specially investigated the subject with t 
` of successfully treating the insect from a horticultural point of view, 
it is desirable to place as much information as possible within reach of 
those who would not Bibi ive be able to obtain it. 
The following is Professor Riley’s account of Zcerya Purchasi :— 
We have, during the year, been conducting a special investigation of 
the habits of and remedies for the eae Cottony Cushion-scale of 
California, an insect which for the last eight years has occupied much 
of the attention of the horticulturists of that State. We have been much 
m a this pest since it was originally sent to us while in Missouri 
y H. Stretch from San Francisco in 1872, and have watched its 
inerease and spread, until it became evident from its alarming prolificacy, 
from the great diversity of its food-plants, from its supposed immunity 
from the attacks of natural enemies, and from the protection against the 
action of insecticides afforded by its mper waxy exeretions, that 
especial study and ex nop were muc 
The following account of the insect is prepared from published 
accounts and ‘on peHiaied correspondence ; from our biologic notes made 
at the office in Washington, chiefly in 1878, 1880, and 1886 ; but more 
especially from our recent experience in the field (which the delay in 
publishing the report has enabled us et partly slit and the obser- 
vations of Messrs. Coquillett and Koebele, whose reports on experiments 
made to destroy it will be found stm in full among the reports m 
agents, 
GEOGRAPHICAL DISTRIBUTION. 
So far as we have been able to learn, up to the date of present writing, 
the Cottony Cushion-scale is found only in AN in Australia, in 
e Africa, and in New Zealand. We shall discuss its introduction - 
to California and its present limitations in that State in subsequent 
sections of this paper, and what we know of its — in the other 
untries mentioned is here considered. 
Ix AUsTRALIA.—As will appear farther on, the ev i Vade 
goes to prove that this insect is indigenous to Australia 
exported from this colony to the two other colonies in whie ito occurs 
and to the United States. We have very few facts as to its occurrence 
in Australia and these are taken at second hand. We have addressed 
communications to a number of naturalists in different portions of that 
country, but their replies have at this writing not been received. From 
the “Report of the Commission appointed by his Excellency the 
* Governor to inquire into and report upon the means of exterminatin 
* the insect of the family * Coccide, commonly known as the * Australian 
R Pun Trimen, dated February 5, 1877, and published by. the 
Government Secretary of Cape Colony as * Government Notice No. 113, 
u 
received as follows :—The Queensland a uthorities simply promised 
inquity and report. The Government of South Australia did not hi Eger 
the insect in question as a native of that colony. The inquiry to 
Victoria was referred to Prof. Frederick McCoy, Director of the 
National Museum at Melbourne, who identified t e insect as à new ` 
Dorthesia, * Mess 
common in Victoria on different kinds of Acacia.” 
pst 
