19 
and tbns to reduce to a minimum the possibility of an extensive 
spread. 
The caterpillar of the gypsy moth (Fig. i6) is a voracious feed- 
er, eating the leaves of nearly every kind of tree or shrub, and de- 
vouring sometimes also grasses and field and garden crops. The 
very fact that it spreads but slowly makes it locally all the more 
Fig. 16. Gypsy Moth, PorthHria dispar, larvae. Natural size. 
(Coonecticut Experiment Station.) 
injurious, since it accumulates in enormous numbers upon infested 
localities. Forests, orchards, gardens, parks, and street shrubs and 
trees may be stripped of every leaf between the first of May and 
the middle of July. 
The insect winters in the egg stage, the eggs being plastered 
in conspicuous masses (Fig. 17) on the trunks of trees and on va- 
rious other objects. They may readily be destroyed by touching 
them with a mixture of creosote oil, 50 percent, carbolic acid, 20 
percent, turpentine, 20 percent, and coal-tar, 10 percent, in sufficient 
quantity to soak the mass. The caterpillar may also be killed on the 
trees with arsenical poisons, but these must be applied in unusual 
quantities, since the gypsy moth is not readily poisoned in the cater- 
pillar stage. Five pounds of arsenate of lead to fifty gallons of 
water will kill the young, but even this can not be depended upon 
for the full-grown caterpillars. These are about three inches long, 
of a sootv or dark grav color. Along the back is a double row 
