No. 4.] SHADE-TREE INSECT PROBLEM. 89 



These insects are strongly attracted to light, and great num- 

 bers of them meet their fate in the globes of arc lamps. 

 This same attraction to light, however, has doubtless been 

 the means of spreading the moths from town to town, since 

 it is found that the oldest infestations are found in the cen- 

 tres of towns where the lights are most numerous. The 

 eggs are laid in compact, hair-covered masses, on the under 

 surface of pear and other leaves, and hatch in about three 

 weeks from the date of laying. From 200 to 400 eggs are 

 deposited by each female moth, the rate of increase being 

 somewhat slower than is the case with the gypsy moth. 

 The menu of the brown-tail moth includes a wide range of 

 ornamental trees, although primarily it must be considered 

 to be a pest of the pear tree. Wherever it is numerous, 

 maples, willows and elms are defoliated to a serious extent. 



For two years this insect was suppressed by the gypsy 

 moth committee, but with the abandonment of the work 

 of that committee in the spring of 1 900 the systematic cam- 

 paign against the brown-tail moth necessarily came to an 

 end. It has been interesting to the writer, living since that 

 date in the infested district, to note the gradual increase and 

 spread of this pest in the vicinity of Boston . Where in the 

 winter of 1899-1900 there were but scattered webs, they 

 may be counted now by the thousand. 



Not the least important feature of outbreaks of the brown- 

 tail moth is the truly terrible irritation caused by the hairs 

 of the caterpillar w T henever they come in contact with human 

 flesh. This irritation is well compared to nettling several 

 degrees intensified, and probably is of a mechanical nature, 

 being produced by the tine, brittle, barbed hairs breaking 

 up in the skin. It is best allayed by the liberal use of vas- 

 eline or sweet oil. Last summer so severe and general was 

 this painful affliction in the Allston and Brighton districts 

 of Boston that the residents of those suburbs petitioned for 

 and received a public hearing at the office of the Boston 

 Board of Health. The nettling of these caterpillars fur- 

 nishes an excellent but painful means of identifying the 

 insect. 



The brown-tail moth is now known to occur in a territory 



