PUTNAM ON PULVINARIA INNUMERABILIS. 337 



death, but such an application is of course not practicable. This subject 

 is worthy of furtlier more careful experiment. Solutions containing soai) 

 would do better, as the oily grease would act as a penetrating medium. 

 Under the 2d head it is quite probable that any poison which would des- 

 troy the wax-protected bark lice would also destroy their unprotected 

 enemies. Under the 3d head I have no definite observations to report, 

 the effect on the trees can only be ascertained by experiments which I 

 , have not performed. Under the 4th head it is plain that to syringe a 

 tree with alcohol at $2.50 per gallon, even if considerably diluted would 

 not pay, and so it is with most of the other articles I have mentioned, 

 but probably some oily substances can be found which will be cheaper 

 in their application. The use of oil as a remedy against the bark-lice 

 has long been well known and was particularly recommended by Dr. 

 Fitch. 



Miss Emily A. Smith recommends the following plan :* "Charge a 

 Hre extinguisher in the usual manner with bi-carbonate of soda and sul- 

 piiuric acid ; add to the water one spoonful of carbolic acid to every eight 

 gallons of water ; apply this to the tree and the force from the extin- 

 guisher will convey the fluid to all parts of the tree alike." This plan 

 has been tried in Peoria and found a success, the applications being 

 made twice on each tree during the time the young lice are hatcliing. 

 The cost does not exceed twenty cents an application. Mr. Riley has 

 suggested that kerosene oil be substituted for tlie carbolic acid, as it 

 would then be effectual even after the waxen coats had foraied.f 

 Making the substitution proposed by Mr. Riley, this is probably the 

 best artificial remedy yet suggested. But before undertaking to destroy 

 the lice artificially, first ascertain what the natur'al enemies are doing, 

 and if these are abundant and at work it may often be better to let them 

 have their own way, rather than destroy them also, unless there is a fair 

 prospect of completely exterminating the bark lice, both on your own 

 trees and tliose of your near neighbors. J 



* American Xatiira/ist. Vol. XII, 1878, page 808. 



+ Canadian Entomologist, Vol. X, 1878, page 177. 



:J Of the ranuT other remedies which have been recommended 1 will mention three that 

 have come under my notice. Our member. Dr. T. J. lies, in June, 1871, after " headlns; in"' 

 his trees washed the remaining limbs with a mixture consisting of "three gallons each of 

 soft soap and water, one quart of carbolic acid."' This appears to have checked the lice for 

 a time, but from some canee the trees finally died. Another of our members, Mr. John Hnnie, 

 informs me that he has successfully treated his trees by boring holes through the bark and 

 tilling them with sulphur. I am at a loss to know how the sap could absorb enough sulphur 

 to kill the lice without injuring the tree it^elf. I think the lice must have disappeared from 

 some other cause, such as the increase of parasites. On a tree thus treated with sulphur 

 which came under my daily notice in 1871, there was no apparent effect whatever either on 

 the tree or the lice. Another remedy which is being continually recommended is the intro- 

 duction of the English sparrow. This bird was introduced into our city some years ago and 

 is now exceedingly abundant, yet I have never on any occasion seen one touch a bark louse, 

 or any other insect, — they appear to subsist almost entirely upon the grain continually being 

 dropped in the streets. 



