Insecls of Shade Trees and Their Control. 67 
hatching from them excavate individual mines, first beneath the bark 
and later deep into the wood, throwing out shredded borings as they 
work along. Two years of feeding in the tree pass before the borer 
matures and transforms to a beetle. 
pps ee 
. 
I'ic. 47.—The cottonwood borer: Male beetle. More’than twice natural size, (Milliken.) 
Remedies —In the case of shade and otherwise valuable trees the 
borer may be profitably killed either by being dug out while young 
or by injection of carbon disulphid (p. 14) into the hole showing 
fresh sap and boring dust, this hole being then promptly plugged 
with putty, clay, or similar substance. It seems as though the young 
borers might also be killed by spraying the infested trunk with 
poisoned kerosene emulsion (p. 12, 13) or miscible oil (p. 12, 13). 
