REPORT OF THE SOCIETY 23 



NOTES ON THE WHITE-MARKED TUSSOCK MOTH. 

 By Dr. J. C. Chapais, St. Denis-en-Bas, Quebec. 



In Eastern Quebec, our orchards were invaded, in the course of last summer, 

 by an insect already known, but which, in 1917, spread itself as a true plague in our 

 region. 



That pest is known under the common name of the White-marked Tussock 

 Caterpillar, which is the larva of the Hemerocampa leiico stigma, in French : VOrgye 

 a taches blanches ou V Hemerocampe marquee de blanc, its common French name 

 being: "Le papillon crepusculaire a toiiffes, marque de blanc." 



The larva of this insect is one of the prettiest that we have. "When matured 

 it is more than an inch long, of a bright-yellow color, with the head and two small 

 protuberances on the hind part of the back of a brilliant coral-red. Along the 

 back, there are four cream-colored brush-like tufts, two long black plumes on the 

 anterior part of the body, and one on the posterior. The sides are clothed with 

 long, fine yellow hairs. There is a narrow black or brown stripe along the back, and 

 a wider dusky stripe on each side." (Saunders). 



Though many entomologists have written that there are two broods of this 

 species in one season, we have ascertained that in Ontario and Quebec there is 

 only one. This has been verified by Mr. Caesar, entomologist at the Guelph 

 Agricultural College, Ontario, who thus corroborates our own assertion. 



The female insect has no wings or simply rudiments of wings. When it emer- 

 ges from its cocoon, by the end of August, it lays from 300 to 500 eggs. It deposits 

 these upon the cocoon and covers them with a whitish, sticky substance which 

 hardens when exposed to the air. The eggs hatch in the following spring, by the 

 end of May, when tiny caterpillars emerge from them and begin immediately to 

 feed upon the leaves of the trees which constitute their nourishment, till they have 

 attained their complete development, after a period of about one month. Then 

 they begin to spin their cocoon on the leaves of the tree where they grow. After 

 about a fortnight the winged male insects and the wingless female insects emerge 

 from their cocoons. 



After it has escaped from its cocoon, by the end of August, the female patient- 

 ly waits the attendance of the male and then begins to lay its eggs as mentioned 

 above. 



To prevent damage and the multiplication of these insects, one must, 1st, 

 have recourse to the hand gathering of the cocoons laden with eggs that are found 

 on dead leaves attached to the bark of trees and, here and there, in cracks of fences, 



