New York Agricultural Experiment Station. 573 



we have observed that so much more dirt would cling to the in- 

 fested roots than to roots which were not infested, that the trees 

 with infested roots were readily distinguishable from the others. 

 Plate XLV, fig. 1, is from a photograph of the roots of two 

 healthy apple trees, freshly dug from soil which was exactly the 

 same as that in which the others were grown. This figure is in- 

 troduced here to show the contrast between the external appear- 

 ance of freshly dug healthy and infested roots. 



In order to make a closer examination of the galls and de- 

 formed roots the soil was removed from the roots shown in Plate 

 XLIV, fig. 2. The result is shown in Plate XLV, fig. 2. From 

 this figure it is evident that most of the galls occur on the larger 

 roots. A closer examination, however, revealed the fact that 

 many of the fibrous roots also were swollen in places, as if a 

 gall had just started, and on others galls half as large as a pea 

 were occasionally found. Plate XL VI shows a closer view of 

 some of the infested roots. A few of the fibrous roots and some 

 of the rootlets are shown to be slightly swollen or bearing small 

 galls. ( 



The trunlc and hrancJws. — Young nursery trees and those newly 

 set out in the orchard show the injurious work of this insect more 

 than older trees. In the summer the bark on the trunks of the 

 young trees often becomes scarred and pitted, as a result of the 

 work of the lice. The young branches, however, show the injury 

 more plainly. Here the lice accumulate in great numbers, fre- 

 (luently almost covering the limbs. They seem to prefer to gather 

 in the axils of the leaves, and also at the tips of the limbs. They 

 are also often found on the leaves. Thus a badly infested branch 

 is easily recognized by the large amount of the woolly-like sub- 

 (Stance which the lice secrete. Plate XLVII is from a photograph 

 of an infested branch of a young apple tree as it appeared in 

 the summer. But few of the lice themselves can be seen, as most 

 of them are covered by the woolly secretion. 



Although the usual method of carrying the species through the 

 winter may be by the winter egg, yet in this climate many of the 

 lice hibernate. They may be found in broken places in the bark 



