19 



have seen no natural enemies preying upon them to any appreciable 

 extent. I have seen black ants carrying canker-worms down the 

 trunks of the trees, sometimes larger than their own bodies, but only 

 in occasional instances. 



" I have also seen, under the same scales with the eggs, large num- 

 bers of a sub-globular, smooth, brownish black Acarus or mite. This is 

 similar to and perhaps identical with the species referred to by Dr. 

 Packard, under the name northrus ovivorus, and which he says he has 

 seen sucking the eggs of the canker-worm. My correspondent, Mr. 

 Tinker, also called my attention to them, and said he suspected that 

 they destroyed the eggs, as he had observed some of these to be shrunk- 

 en where the mites were present. I have repeatedly examined these 

 Acari, but have never detected them in the act of sucking the eggs. I 

 have also kept quantities of eggs and acari shut up together in a box 

 for days, but in due time the eggs nearly or quite all hatched. I have 

 also found the same acari in equal numbers under bark where there 

 were no canker-worms. My own observations, therefore, do not lead 

 me to attach much importance to them as canker-worm destroyers. 



"Remedies. — The following remedies against this insect are given in 

 the order in which they are to be applied, commencing with the ap- 

 pearance of the moths in the spring : 



"1st. Prevent the passage of the moths up the trees. The most ap- 

 proved plan heretofore used, is to put a canvass or other cloth band, 

 six inches or more wide, around the trunk and besmear it with a mix- 

 ture of tar and molasses, applied every other day. Roofing felt be- 

 smeared with refuse printers' ink has been recently suggested as 

 preferable. The method suggested in this Report is, to put a band of 

 rope or closely twisted hay around the trunk, and over this a tin band 

 about four inches wide, placed so that the rope shall be at the middle 

 of the tin, making a closed cavity below and a free edge of the tin 

 above. The time to use these appliances is, mostly in the month of 

 March ; but also at other times when the weather is sufficiently open 

 to permit the insects to run. 



"2d. If the moths are prevented from ascending the tree they will 

 deposit their eggs below the obstruction, and for the most part near 

 to it. These eggs can be destroyed by a single application of kerosene 

 oil. 



"3d. If the moths are not prevented from ascending the tree they 

 will deposit their eggs mostly on the under side of the loose scales of 

 bark on the upper part of the trunk and large branches. Many of 

 these can be destroyed by scraping off and burning the scales. 



"4th. If all precautions have been neglected, and the eggs have 

 been permitted to hatch, then as soon as the worms are large enough 

 to be easily seen, jar them from the trees and sweep them away with 

 a pole, as they hang by their threads, and burn or otherwise destroy 

 them. Strong washes, such as Paris-green water, or suds made from 

 the whale oil soap, thrown upon the trees with a garden syringe, will 

 also materially check their depredations. 



"5th. If the worms have matured and gone into the ground for 

 winter quarters, plow the ground late in the fall, so as to expose the 

 pupae to the frost and the action of natural enemies. The effective- 



