100 PARASITES OF GIPSY AND BROWN-TAIL MOTHS. 



the stripped trees to others in the vicinity, and it is an unmistakable 

 fact that such migrations, which have several times been mentioned 

 in the earlier reports of the State superintendent of moth work, are 

 now decidedly less frequent, even without taking into consideration 

 the greater territory throughout which the moth is now present in 

 destructive abundance. Although the junior author has personally 

 visited large numbers of outlying colonies of the moth in the course 

 of 1908, 1909, and 1910, he has yet to see one in which the disease 

 had not appeared coincidently with the development of the colony 

 to the stripping stage, if not slightly in advance of that time. 



It is probably safe to say that such conditions as are described in 

 the first annual report of the superintendent of moth work as pre- 

 vailing over a large territory in the old infested section during 1904 

 and 1905, will probably not immediately recur in the history of the 

 gipsy moth in eastern Massachusetts. That something approaching 

 this may result in parts of New Hampshire is well within the bounds 

 of probability, and that the conditions will be very bad in that State 

 during the course of the next few years as well as in some of the 

 towns in Massachusetts may be accepted as most probable. What- 

 ever may be the condition presented by the older infested sections 

 in eastern Massachusetts five or ten years from now, the only hope 

 of preventing an ever-increasing wave of destruction from spreading 

 over western Massachusetts, across New Hampshire and Vermont, 

 and over the border into the State of New York, seems to lie, as 

 always, in an increasing expenditure for hand suppression or in the 

 success of the experiment in parasite introduction. Through the 

 methods now in operation it is probable that the pest will very largely 

 be prevented from making long " jumps," which would otherwise 

 have been of frequent occurrence, but the slower and more steady 

 natural spread, through the agency of wind, and probably, when the 

 headwaters of the Connecticut, Hudson, and Ohio are reached, by 

 water, must be considered in every attempt to discount the future. 

 It was taken into consideration when the future of the parasite work 

 was decided upon. 



In the course of the studies of the parasites and parasitism of native 

 insects which have been undertaken in connection with those of the para- 

 sites of the gipsy moth and the brown-tail moth, no less than three spe- 

 cies have been encountered which are controlled to some extent by a 

 disease which bears a very close superficial resemblance to the " wilt" 

 of the gipsy moth. These are the white-marked tussock moth, the 

 tent caterpillar, and the "pine tussock moth." 



The white-marked tussock moth (Hemerocampa leucostigma S. & A.) 

 is well known as a defoliating pest in cities, and has been so abundant 

 as at times to become a rival of the gipsy moth in its destructive 

 capacities in certain of the larger cities in southeastern New England. 



