10 Farmers’ Bulletin 1169. 
(7) any other information that may help in identifying the insect 
and determining the proper remedy or control measure suitable to the 
condition of the correspondent. Notes should readily correspond to 
labels on specimens, and may be separate or embodied in the letter. 
(4) Shipping specimens.—Packages not exceeding 4 pounds in 
weight are most conveniently and cheaply sent by parcels post. Bulky 
packages may be sent by freight; fragile, by express. They must 
always be sent prepaid unless otherwise authorized. 
THE PRINCIPLES OF SHADE-TREE INSECT CONTROL. 
As elsewhere stated, the feeding habit of the insect that is doing 
the injury is the main factor in determining the kind of remedy to 
be applied. This is particularly true of the insects that feed in the 
open, i. e., above ground and on the outside of the plant. In most 
such instances the principle is very simple: We poison the food of the 
insect that bites its food before swallowing it and kill the sap-sucking 
insect’ with external applications—contact insecticides as they are 
called—which are usually caustic or oily liquids. In a great many 
cases, however, and especially in insects that live in the interior of 
the plant tissue, like leaf-miners, gall-makers, borers, and under- 
ground workers, be they biting or sucking insects, our method of 
attacking them must necessarily be different. A vital principle of 
successful insect control is wholesale destruction of them. In emer- 
gencies, however, and especially where a single insect is capable of 
doing serious harm, we do not hesitate to undertake their destruction 
singly, as in the case of root or stem borers. Again, we often find 
through a knowledge of their habits that some biting insects, for 
instance, are more cheaply and effectively fought in some other stage 
of their lives than in that in which they feed; for example, the de- 
struction of the white-marked tussock moth in the egg stage. 
It is evident from what has been stated above that in spraying 
promptness and thoroughness are vital elements. The earlier in its 
life the insect is killed the more quickly it is killed and the less harm 
it will have done; the more completely the foliage is covered with 
spray the more certain is the early killing of the insects and the more 
of them will be killed. Likewise, with the sap-sucking insects the 
more thorough the application the greater the number of the insects 
that will be hit and killed. Zhoroughness means the complete cover- 
ing of the insect’s food in one case and of all of the insects in the 
other. 
TREE INJECTIONS: WORTHLESS OR WORSE. 
A. word on the subject of tree injections is imperative. Perhaps in 
no other respect are unsophisticated tree owners more imposed upon 
than in the matter of injection of various cure-all preparations under 
