Insects and Fungi Attacking Trees, Etc. 333 



of tar or printer's ink, or of tin or other kind of troughs 

 with oil in them, around the trees to prevent the female 

 insects from reaching the branches is effectual provided 

 the band is kept covered with soft ink, tar or tanglefoot, or 

 the trough is well filled with oil when the insects are moving, 



Fig. i8o. — Canker-worm. 

 (Riley: Circular Xo. 9. 2d Series, Dept. Agr., Fig. i.) 



i.e., at any time when there is no frost in the ground, on 

 warm nights from November 15th to April 15th. The more 

 satisfactory remedy, except for very tall trees, however, is 

 to give the insects no attention until the eggs begin to hatch 

 out, and then to destroy the larvae by spraying with Paris 



Fig. 181. — Canker-worm. 

 (Riley: Circular Xo. 9, 2d Series, Dept. Agr., Fig. 3.) 



green or arsenate of lead used as for the elm-beetle, making 

 two applications, one when the first eggs hatch and then again 

 in from five to eight days, according to the weather, or when 

 all of the eggs are hatched out. Success in this work depends 

 upon how much arsenate is used and how thoroughly the 

 foHage is covered with it. For the amount of arsenate to use 



