THE BROWN-TAIL MOTH l*2o 



MEANS OF DISTRIBUTION. 



The principal spread takes place through the llighl of 

 the moths just after emergence. "These insects fly freely 

 and have a habit of soaring upward above the tree tops 

 and buildings. When the moths in their nocturnal flights 

 have thus risen in the air, they are often drifted by the 

 wind over long distances." (Fernald and Kirldand.) 

 Thus the strong winds of mid-July, 1897, are known to have 

 carried the moths far northward from the point of origin 

 in Massachusetts and similar winds were undoubtedlv re- 

 sponsible for the unusual spread northward and eastward 

 in 1904. 



It should be noted in this connection that as the moths 

 are strongly attracted by lights they usually swarm around 

 the electric lights in the center of a town and are always 

 found first in towns and cities, which become centers from 

 which the surrounding country becomes infested. This is 

 a fortunate feature of their spread, for being thus naturally 

 concentrated it is much easier to control the pest on the 

 few town trees than if scattered over the country. 



Due to this attraction by lights, the moths have often 

 been spread by electric and railway cars, and possibly 

 steamers, but particularly electrics, the moths flying into 

 the cars and being carried some distance. It has been no- 

 ticeable in a newly infested territory that the infestation 

 runs along the electric car lines in advance of the main 

 spread. Like those of the gypsy moth, the young cater- 

 pillars have the habit of dropping down from the trees by 

 spinning a strand of silk by which they are suspended, so 

 that they may be picked up by any passing vehicle or may 

 crawl upon it and thus be carried. Undoubtedly this often 

 occurs, but as the spread takes place so much more rapidly 

 by the flight of the moths, it is of minor importance. 



FOOD PLANTS AND INJURY. 



The pear is the preferred food plant of the caterpillars 

 and is usually first infested where available: the apple 



