370 A Practical Hand Book 



used, and oils, soaps and similar materials, called contact poisons, 

 are the more usual substances for this purpose. Contact poisons 

 appear to destroy insects by covering them, or at least the 

 openings of their breathing organs, with a film, thus suffocating 

 them, and it is at once evident that unless a sucking insect be 

 actually touched by some of the contact poison, the treatment 

 will fail. With biting insects the poison may be spread over the 

 tree to wait until the insect in its feeding reaches and swallows 

 it; with sucking insects only those touched by the poison at the 

 time it is applied will be destroyed; and if we remember that 

 many of the sucking insects are exceedingly small, the necessity 

 for the most thorough application possible of the poison becomes 

 evident. 



GENERAL FEEDERS. 

 The Leopard Moth. 



This insect is a native of Europe. It reached this country at Ho- 

 iDoken, N. J., about 1881, and since that time it has spread east- 

 ward, mainly along the coast, and is now found quite abundantly 

 as far east as eastern Massachusetts. It attacks many kinds of 

 shade trees and shrubs, and appears to be most injurious in and 

 near the larger cities and towns. 



The adult insect is a good sized moth with white wings bearing 

 numerous blue-black spots. It appears during the latter part of 

 May, from which time specimens may be found till late in Septem- 

 ber. The eggs are laid in sheltered places such as crevices of the 

 bark, usually on the small branches, and on hatching, the young 

 borers work through the bark to the wood. Here they feed, work- 

 ing downward. When the branch becomes too small for the rap- 

 idly growing borer, it leaves it and enters another. Sometimes the 

 boring is along the centre of the branch ; sometimes it takes the 

 form of a large cavity, and sometimes it passes around the branch 

 and girdles it. By winter the borer is usually about half grown, 

 and has entered one of the larger branches, leaving weakened 

 smaller ones behind. 



