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first doue in this department, when 12 men were employed to clean tlie 

 trees, benches, walls, and stonework in the parks. The first autumn of 

 our work we collected 13 bushels of these cocoous and egg masses, leav- 

 ing those cocoons that were apparently j)arasitized until the final clean- 

 ing. The large elms on the Mall were thoroughly cleaned with steel 

 brushes made for the work, and each tree received a wash to destroy 

 any insects that might be in the crevices of the bark. This work of 

 collecting (and burning in the fnrnace) has been carried on each year as 

 the force would allow, in this way keeping them in subjection. We 

 now treat them in four different ways : 



(1st) By hand-picking, of which bushels are each year taken from the 

 trees with tools especially adapted for this work. 



(2d) By jarring the larvje down with a pole, so arranged that a 

 blow from a mallet on a projection placed at tbe large end of the i^ole 

 will jar any down that may be on the branches. With a sudden blow 

 most of them will fall to the ground, when they can be crushed. 



(3d) By poisoning the foliage with London purple, which is quite 

 effective and used especially on very large trees that can not be treated 

 otherwise. 



(ith) By poisoiiing or spraying the trunks of large trees with an 

 emulsion of petroleum and carbolic acid. This i^enetrates most of the 

 cocoons sufficiently to kill the inmates, the disadvantage being that 

 it kills the parasites too. This method is only resorted to when the 

 egg masses are very numerous and we are short of help, and as a means 

 of reducing the next brood. Large numbers of trees were so treated 

 this season to arrest the late summer hatchings. 



The next insect in abundance and destructive working was the Bag 

 Worm, Thyridopteryx ephemera'formis. Whole portions of the parks 

 were literally stripped of their foliage ; many of the trees on the drives 

 were nearly as bare as in winter. So abundant were they that the 

 branches were strung with their cases, and with one push of the instru- 

 ment prepared for collecting them, a handful of these cases would be 

 taken. Four kinds of tools were made for this work, and the cases were 

 collected and destroyed. In this way nearly 22 bushels have been col- 

 lected and destroyed. 



The Dalanas have always been abundant in the parks, and as many 

 as 15 pounds of caterpillers have been taken from a single tree. These 

 are collected while massed, as is their habit, and then destroyed. 



Hyphantria cunea is very abundant in our parks and has been de- 

 stroyed by cutting down the webs as far as was j)ossible. If the tree 

 was too valuable, they have been twisted out with poles made especiallj" 

 for this work. In some cases spraying has been resorted to, but as this 

 does not remove the unsightly web, the most practical thing to do is to 

 remove the whole colony. 



Glisiocanipa americana has this year appeared in our parks for the 

 first time, and in great abundance. The webs that appear on the trees 



