29 



frequently stated that these larvge feed upon the fatty parts of the 

 caterpillar, without injuring any of its vital i^arts. It is more 

 likely that they obtain their hoiirishment by absorption through the 

 skin. This is known to be the case with many larvae which inhabit 

 galls — such as the Hessian-fly (Cccidomyia destructor, Bay) — and it 

 is very probable that all internal parasites obtain their nourishment 

 in this manner. Their jaws, instead of curving toward each other 

 as do the jaws of other insects, curve downward, and appear to 

 have been designed more for retaining the larva in its place than 

 for mastication, 



REMEDIES. 



The method usually pursued for exterminating these insects is to 

 destroy the female moths before they have deposited their eggs, or 

 at least to prevent them from depositing them upon the trees. To 

 accomplish this, many patent inventions have been given to the 

 public, but these have usually been too expensive or to difficult of 

 application to bring them into general use. A very simple method, 

 and one quite as effectual as any of these, is to place paper bands 

 around the trunks of the trees and cover them with tar or some 

 other sticky substance. The best paper for this purpose is tarred 

 building paper, such as carpenters sometimes use in siding up a 

 building before the clapboards are nailed on. There are two kinds 

 of this paper ; one of a brownish color, resembling pasteboard, the 

 other black. This latter kind is much preferable to the former, and 

 should always be used whenever it can be obtained. It is sold in 

 large rolls, each roll being composed of only one strip, which, when 

 unrolled, is wide enough to be cut into four strips of equal width. 

 From the end of one of these strips cut off a piece long enough to 

 reach around the trunk of the tree and overlap about one inch. 

 Wrap one of these pieces around the trunk, resting the lower edge 

 of the paper upon the ground, and fasten it to the tree with two 

 strong cords, the upper one being tied around the band about one 

 inch' below its u]3per edge, the second one about midway between 

 this one and the surface of the ground. The tar should be applied 

 to the band above the upper cord, and should be renewed before it 

 becomes hard, otherwise the moths will pass over it. If a small 

 quantity of castor oil is mixed with the tar, the latter will not 

 harden so rapidly as it would if pure. Great care should be taken 

 not to have any part of the trunk of the tree below the band 

 exposed to view, the object being to prevent the moths from deposit- 

 ing their eggs upon any part of the tree. Should any part of the 

 tree below -the paper band be exposed to view, it should be mounded 

 up with earth. In the latitude of Northern Illinois the tar should 

 be applied to the bands about the middle of October, and should be 

 renewed for about six weeks afterward, or until all of the moths — 

 or grubs, as they are commonly but incorrectly called — are de- 

 stroyed by the cold. In more southern latitudes the moths probably 

 begin to rise earlier in the season, and in such places it will be 

 necessary to apply the tar earlier in the season than the date given 

 above. Should the orchard also be infested with the Spring Canker- 

 worms {Anisopteryx vernata, Peck) — the moths of which rise from 

 the ground in the spring— the paper bands should remain on the 



