CANKER-WORM. 107 



I have already referred to the fact that the moths deposit their eggs 

 almost exclusively upon the inner surface of the loose scales of bark, 

 and not upon the body of the tree. Why they should always attach 

 their eggs to the dead bark over them, rather than to the smooth living 

 bark under them, it is difficult to conjecture, but that tney do so puts 

 them, to a greal extent, at our mercy. For it is evident that by scra- 

 ping off the dead bark on the trunk and branches, any time between 

 the laying and the hatching of the eggs, so large a proportion of the 

 eggs will be destroyed that the comparatively few wliich may escape 

 will not be numerous enough to effect any serious amount of damage. 

 The bark and eggs thus scraped off should always be caught upon a 

 sheet or a number of newspapers, and burned. 



RECORD CONTINUED. — TIME OF HATCHING. 



April 27. — About a week ago I saw a few young Canker-worms on 

 the trees, but they were evidently premature stragglers, as the foliage 

 had then scarcely begun to open. But to-day, the red currant being in 

 pretty full bloom, and the leaves on some of the apple trees being half 

 expanded, I found almost every tuft of leaves which I examined occu- 

 pied by two or three minute Canker-worms. 



May 11. — Canker-worms not injured by frost. The first part of May, 

 since the Canker-worms hatched, has been cold and rainy, and on Fri- 

 day the fifth, there was a sprinkling of snow, and water froze at night. 



Yisited the Canker-worms to-day and found them iu good condition. 

 The cold weather had, at most, only checked their growth a little. The 

 worms vary much in size, implying that the eggs do not all hatch at 

 once. Many of them are now three-tenths of an inch long. ISToticed 

 the ease with which they are jarred from the trees. A slight rap upon 

 a branch will let off a shower of them, all hanging by their threads. 

 I tried the plan of sweeping them away by passing a pole horizontally 

 under the tree. It is evident that a vast number of them can be swept 

 off in this way, and could be destroyed by having a brush fire at some 

 one or more convenient points, over which the pole could be held for 

 a few minutes. 



APPROPRIATENESS OF NAME. 



May 23. — "Whilst looking at the apple trees blasted by this insect, I 

 was struck with the appropriateness of their popular name of Canker- 

 worm. By eating numerous irregular holes through the leaves, they 

 interrupt the flow of sap, so that the leaf becomes withered and brown 

 before it is wholly eaten, and the tree presents the appearance of having 

 been scortched by fire. 



