CANKER-WORM. 115 



tar entirely harmless, but that it dries so rapidly that it requires to be 

 renewed every day. 



With regard to the particular point now under consideration, how- 

 ever, namely : the application of kerosene oil to the trunks of trees 

 for the purpose of destroying the eggs of the Canker-worm moth, my 

 own experiments, above detailed, seem to show conclusively that it is 

 entirely harmless, at least, in the spring of the year ; and this is the 

 time when it is to be applied for this purpose. But a reasonable caution 

 as to the extent of its application should be exercised, until tested by 

 further experience. 



NATURAL ENBMIES. 



These insects have been observed to be destroyed by birds, by a 

 number of predaceous ground beetles, and by several species of para- 

 sitic flies. My own observations upon this branch of the subject have 

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

 of a sub-globular smooth, brownish-black acarus or mite. This is sim- 

 ilar to, and perhaps indentical with, the species referred to by Dr. 

 Packard under the name of JVoihrus 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 

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

 shrunken 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. 



SUMMARY OF REMEDIES. 



The following remedies against this insect are given in the order in 

 which they are to be applied, commencing with the appearance of the 

 moths in the spring. 



'"Ist. Prevent the passage of the moths up the trees. The most ap- 

 proved plan heretoJ[ore used, is to put a canvass or other cloth band, six 



