225 
` The following scheme represents the life history of this insect ;— 
Ovum or egg. 
| 
| | 
Mobile larva. Mobile larva. 
| 
Small round scale. Small oval scale. 
| | 
Large scale. Pupa. 
| 
Winged insect. 
| 
Egg. 
Methods of Treatment. 
We are in the main indebted to the officers of the division of 
detailed account, and 1 have thought it would be of service to quote the 
following pages from the fa of Mr. D. W. Coquillett,* who has done 
so much to aid the orange growers of California in their efforts to 
rus this and other insect pests 
The Gas Treatment for the Red Scale of California. 
“ Briefly speaking, this process consists in covering the infested tree 
with an air-tight tent, and afterward charging the tent with hydrocyanie 
gas. The material commonly used in the construetion of the tent is 
what is known as blue or brown drilling. A few ns have 
ducking instead of the drilling, but this is much inferior to the latter; 
in the ducking the гето of which it is composed extend only 
lengthwise and crosswise, reas in the drilling they also extend 
diagonally-—this belonging to aie class of goods to which our merchants 
apply the term “ twilled”—and for this reason the drilling is both 
stronger and closer in texture thats the ducking. 
the tent is sewed upit is given a coat of black paint, as it has 
been ee es that tents treated in this manner last longer than those 
on — been simply oiled with linseed oil. Some persons mix à 
quantity ofsoap suds with the paint in order to render the latter 
cov the ten usin i this purpose 
covering he š small quantity of whiting or chalk (carbonate te of lime, 
Ca Соз), is did M “this sizing with or without the addition of lamp- P xs 
black. A few make use of the mucilaginous juice of the comin 
Cactus (Opuntia a Salm.) for this purpose ; to obtain ai the 
Cactus leaves or stems are cut or broken up into pieces, thrown into a 
barrel and covered ih der after which they are allowed to soak for E — 
* Т], S. Department of Agriculture, Division of Entomology. Bulletin No. 23. 
