50 TlIK BKOWN-TAIL MOTH. 



in Boston harbor and along the north shore are irenerally 

 infested by the brown-tail moth. It is entirely probable 

 that moths attraeted by the bright lights 11}' to and alight 

 on passing vessels, and in this way the insects already may 

 have been carried accidently to many seaports. The dan- 

 ger of spreading the moth by shii)})ing is of course greatest 

 on the coastwise steamers, where the boats make landings 

 before the moths have laid their eggs and died. 



AVhen the moths are flying, they arc strongly attracted to 

 litrht. In tracing; the distribution of the moth in the winter 

 of 1898-99 it was found that the most promising places to 

 search for the insect were in the centres of population, 

 where electric and other lights were massed in greatest num- 

 bers. It is not difficult to understand how the swarming 

 insects driven by the wind from the place of emergence fly 

 onward to the nearest mass of light. This tends to bring 

 about the infestation of the central portions of cities and 

 towns before the pest finds its way to the outlying residen- 

 tial or farming districts. 



Again, the flying moths enter brightl}' lighted electric and 

 street cars. At the flying season warm weather is the rule, 

 and oi)en car windows give the insect easy entrance. Mr. 

 Kirkland has repeatedly seen the female moths in rai)idly 

 moving electric cars and on two occasions in local railroad 

 trains. 



Aside from the i)rinci})al means of distribution mentioned, 

 it is necessar}'^ to consider the dr()})ping of caterpillars on 

 teams, and the danger from nursery stock grown in the in- 

 fested district and shipped to customers living at a distance. 

 In connnon with other cater})illars, the brown-tail moth 

 larvse have a ha])it of spinning down on silken threads from 

 their feeding places, and hanging for some time susi)ended in 

 the air. Where the}' are feeding on street trees, they are 

 fre(juently intercepted by passing teams and are thus carried 

 iVctin pliK'c to place. In the very thorough studies of the 

 distribution of the gypsy moth made by Mr. E. II. Forbush 

 sonu' years ago, it was shown that one of the chief aids in 

 spreading the moth was the regular continued traffic of milk- 

 men, grocers and others. The spinning habits of the brown- 



