96 



ENTOMOLOGICAL SOCIETY. 



there are 15 or 20 different species of trees, it was noticed last spring that every tree of 

 the wild cherry had two or three nests of these caterpillars, while not another tree in 

 the plantation was affected. 



Another difference between these two insects appears in the construction of their 

 cocoons. Those of Clisiocampa Americana are formed of a double web, the outer one 

 loosely woven and filled with a powderly substance resembling sulphur. They are 

 usually hid in some out cf the way place, as under rails, boards or rubbish. Those of 

 Clisiocampa disstria have none of this powdery substance and are more frequently formed 

 inside of the leaves hanging on the trees. On St. Joseph's Island last summer, I 

 saw hundreds of maple3 and other forest trees upon which every leaf contained one of 

 these concoons, even the native spruces were so full of them that they appeared as if 

 packed in wool. 



4 Canker-Worms. — (Paleacrita verndta and Alsophila pometdria.) — Canker-worms 

 have been very abundant in many parts of the country for a number of years past. 

 There are also two species of these, but they resemble each other so closely that to the 

 causal observer they differ only in name. One is known as the Spring Canker-Worm 

 {Paleacrita verndta) (Fig. 63), and the other as the Fall Canker-Worm (Alsophila 

 pometdria) (Fig. 64). One of the most noticeable differences in the two species appears 

 in the egg stage. The eggs (Fig. 63 a and b) of the Spring Canker-Worm are oval in 

 form and are laid in the spring in irregular patches hidden under loose bark or in 

 expanding buds. 



Fig. 63. 

 Those of the Fall species are shaped like miniature flower pots, are ranged in regular 

 rows in masses (Fig. 65, a, b, c), and deposited in the late autumn in some prominent 

 place on the tree. The larvae of both species (Fig. 63 c and 65/) make their appear- 

 ance with the opening of the leaves in the spring. They reach their full size in about 

 three weeks and are then about an inch in length. On account of their peculiar 

 method of travelling, by alternately looping and extending their bodies, they are com- 

 monly spoken of as " measuring worms." They have another peculiar habit when dis- 

 turbed of suddenly dropping from the tree and suspending themselves in mid air by a 

 delicate silken web which is spun as they drop. Their appearance in this position is 

 graphically described in the following letter which I received from a correspondent 

 laBt June : — 



Fig. 65. 



Brighton, June 6th, 1898. 



Dear Sir, — Last evening my husband said, " Come with me, I wish to show 

 you a sight." We went into the orchard. "Now," says he, "see that tree over 



