108 



and as the skins become dry and are blown about by the wind the hairs 

 may be quite generally disseminated. When the hairs alight upon the 

 human skin they cause an irritation which, upon rubbing, may develop 

 into inflammation. In New Hampshire this phase of the insect's pres- 

 ence has already become in evidence. At Portsmouth a clothes reel 

 was near a tree infested by the caterpillars. The famity were greatly 

 troubled through the summer by extraordinary irritations of the skin, 

 for which they were unable to account, but which were doubtless due 

 to caterpillar hairs blown from the pear tree. In the same city a 

 gentleman in removing a caterpillar which had landed on his neck 

 scattered some of the hairs, which produced an eruption similar to but 

 considerably worse than that produced by poison ivy. 



The food preferences of the insect have been shown quite markedly 

 in our observations. Pear seems to be the favorite food plant, with 

 apple, wild cherry, plum, and hawthorn following along in about the 

 order named. 



AN EXPERIMENT WITH BLACK FLIES. 



By Clarence M. Weed, Durham, N. H. 



In the resort regions of northern New Hampshire the black flies 

 have long been recognized as one of the most annoying pests for the 

 summer visitor, as well as for the resident citizen. I have had, from 

 time to time, appeals from hotel managers for help in subduing the 

 pest, but until this year have had to confess that I knew of no probable 

 solution of the problem. For several years I have had under observa- 

 tion a colony of black-fly larvae living on the flat rocks of the outlet 

 to our college reservoir, and have often tried to discover an effective 

 means of killing them. 



When studying the recent literature concerning mosquito remedies, 

 the property of phinotas oil, which leads it to sink to the bottom in 

 water, led me to think that possibly here we had an agent for destroy- 

 ing Simulion larvse. Last June, in order to test the theory, I sent 

 my assistant, Mr. A. F. Conradi, to Dixville Notch, N. H., where 

 these pests have for many years been especially troublesome, with 

 specific instructions to find the breeding places of the flies, and to 

 try the effect of the phinotas oil with which he was provided. 



The Dixville Notch region was peculiarly favorable as to situation 

 for an extended experiment in subduing black ffies, for it is a compar- 

 atively small area, surrounded by mountains over which no flies from 

 other localities would be likely to come. A large part of the encom- 

 passed area is taken up by a beautiful lake. Upon arrival Mr. Con- 

 radi made a careful survey of the entire locality, finding no flies 

 breeding in the swiftly running shaded streams along the mountain 

 sides, but finding vast numbers breeding in shallow, sunlit waters at 



