4 FARMERS’ BULLETIN 675, 
the order for which preference is shown, service, crab, and mountain 
ash being more often attacked than the others. 
The relation of native host trees to the local distribution of the 
borers is important. Frequently a clump of these trees growing 
in a neglected field or those growing in the woods will be infested 
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lic. 8.—Diagram of orchard illustrating the tendency of the adult female roundheaded 
apple-tree borers to group their eggs about the places where they develop. 0, o 
Represent trees; % represents trees from which male and female beetles issued in 
1914; figures represent number and position in the orchard of eggs deposited in 1914, 
Note how eggs are grouped about the two orchard trees from which females issued, 
the lot containing old infested apple trees and the woods in which the borers breed in 
service trees. (Original.) 
and will year after year be a source, and possibly the principal source, 
from which adult insects are produced to fly out and deposit eggs 
in adjacent orchards. 
In exceptional cases peach, cherry, and plum trees are said to be 
attacked by this species, but this occurs very rarely, the common 
peach borer being the larval form of an entirely different insect. 
