18 



found in the smallest moths only fifteen or twenty eggs, whilst the 

 largest contain from one hundred and forty to one hundred and fifty. 



" As the season for laying eggs is now past, I have made a number 

 of examinations with a view of determining definitely where the eggs 

 are deposited. Whilst the moth of the tent-caterpiller covers hereggs 

 with a water-proof varnish, and deposits them on the exposed twigs, 

 the canker-worm moth does not so protect her eggs, and only secretes 

 enough of a glutinous fluid to stick the eggs to the bark. She, there- 

 fore, always seeks some other protection, and this is furnished al- 

 most exclusively by the loose scales of bark. In accordance with this 

 statement, no eggs are found on the twigs or the small smooth branches. 

 Dr. Harris states that the eggs are deposited ' in the forks of the small 

 branches, or close to the young twigs or buds.' But 1 must conclude 

 that Dr. Harris did not make this statement from his own observa- 

 tion. I have recorded above, that in cold or stormy weather the female 

 moth, after she has ascended the tree and passed out upon the 

 branches, often seeks the slight and only available shelter afforded by 

 the forks of the twigs, and it was natural to expect that she w r ould 

 deposit her eggs there. But if she ever so deposited them, it must be 

 very rarely and exceptionable. After a diligent search, with the aid 

 of a lens, on several different occasions, upon heavily infested trees, I 

 have never succeeded in finding any of the eggs in this situation, nor 

 elsewhere under the scales of bark, with the solitary exception above 

 referred to, of the protection afforded by the crumpled leaves and cones 

 of Phycita ncbulo* 



" A corroboration of this view is furnished by a remark of my corres- 

 pondent, Mr. J. Tinker, of Wisconsin, who, speaking of these insects 

 which have been very destructive upon his place, incidentally re- 

 marks : ' They do not bother small smooth barked trees, either in the 

 nursery or orchard." I may here add that, in a subsequent letter, Mr. 

 Tinker stated that he had found the eggs of this insect in the dried 

 apples which had adhered to the tree though the winter. 



" 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, it is difficult to conja'c- 

 ture, but that they do so, puts them, to a great extent, at our mercy. 

 For it is evident that by scraping off the dead bark on the trunk and 

 branches any time between the laying and the hatching of the eggs. 

 BO large a proportion of the eggs will be destroyed that the compara- 

 tively few which 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 number of newspapers and burned. 



"Natural Enemies. — These insects have been observed to be des- 

 troped by birds, by a number of predaceous ground beetles, and by 

 -peciesof parasitic Hies. My own observation upon this branch of the 

 subject have been very limited, and mostly of a negative character. I 



" Note.— An interesting instanc i" this habit of the canker-worm moth was communicated 



t>> me by Mr. Elmer Baldwin. He stated thai mi one time his orchard became infested -with those 

 insects, and that at the same time the leaf-crumplers were very numerous and troublesome, ami 

 Unit the moths availed themselves of the shelter thus afforded for the deposition of their eggs 

 to such .in extent thai be regarded it as one of his mosl efficient modes of getting rid of the canker- 

 worms 1 i gather and destroy the crumpled nests of Phycitae, thus destroying two noxious insects 

 1 ion. 



