1906.] 



PUBLIC DOCUMENT Xo. 73. 



143 



How THE GYPSY MOTH is SPREAD. 



The spread of the gypsy moth in eastern Massachusetts 

 and across the State line into southern New Hampshire has 

 resulted chiefly from human agencies. The female gypsy 

 nioth does not fly, and the natural spread of the insect is 

 therefore slow. The principal means of distribution by 

 human agency is the transportation of caterpillars of the 

 moth upon vehicles. This occurs mainly in the spring and 

 early summer before the caterpillars have grown too large 

 to spin down on their threads from the trees. As in an 

 apple orchard where canker worms, when numerous, drop 

 down on fine threads upon the head and shoulders of the 

 passer beneath, so along a street overhung with the arching 

 branches of shade trees which are badly or only considerably 

 infested the small gypsy moth caterpillars spin down. 

 "Whether a vehicle stands or passes beneath badly infested 



