268 REPORT OF THE DEPARTMENT OF ENTOMOLOGY OF THB . 
from crawling back. Fruit trees located near infested forest or 
shade trees are also banded to prevent invasion by the cater- 
pillars. The bands in use are of two kinds: First, sticky sub- 
stances that will not harden too quickly. Prominent among these 
are a mixture of tar, one part, and raw oil, two parts; raupenleim; 
and a mixture of lard and sulphur, equal parts. ‘To prevent 
injury to the bark these substances should be smeared on strips 
of tough paper a foot or more wide and tied about the trunk 
about midway between the ground and large limbs. Sticky fly 
paper is often used in a similar manner. Second, mechanical 
obstructions such as a band of cotton wool or waste, or a strip 
of tin fastened around the trunk so that the lower edge flares 
out about two inches, thus preventing the caterpillars from pass- 
ing. The insect traps made on the same principle and now on 
the market will answer the same purpose. 
Too much should not be expected of the bands as they are of 
value only in keeping out caterpillars which may crawl from 
other trees or which have been jarred out or otherwise dislodged 
from. the tree and seek to return. | 
A very common mistake is to put the bands on too late in the 
season. If the intention is to prevent an invasion from infested © 
_ trees near by, the bands should be put in place not later than the 
middle of March. j 
Spraying.—Thorough spraying with pure arsenicals has proven 
very satisfactory in cases where the poison was applied before the 
caterpillars were half grown. When the first application is 
delayed until they are past this point it seems to have much less 
effect. Paris green, arsenite of lime and arsenate of lead have 
been used. While both Paris green and arsenite of lime have 
been reported satisfactory, arsenate of lead has some points of 
especial merit. It seems to be more certain in its action and 
adheres to the foliage longer. This arsenical is now on the 
market; but can be made at home by following the directions 
given in Bulletin 159.. It is manufactured by the Bowker 
Chemical Company, Boston, Mass., The Alder Color & Chemical — 
