186 THE CANADIAN ENTOMOLOGIST 



nosis was thrown in doubt and the true cause discovered. Though 

 this type of injury is very common in British Columbia and ap- 

 pears to have been noticed quite widely in the United States and 

 Canada, the amount of actual harm which the mites accomplish 

 in this way is questionable, and is probably of little importance 

 in most cases. Parrott (1 and 2) who appears to have been the 

 first to have recorded this species in America, says that this species 

 is very common on apple foliage in the United States, that it is 

 more common in the United States than on the continent, and 

 that it seems to have possibilities of developing to greater economic 

 importance. P. J. O'Gara (3) who records this mite from Southern 

 Oregon, noticed its work on the apple foliage, which, however, 

 he did not regard as serious. He states that the mite is chiefly 

 important as a pest of pears, the foliage, terminals of twigs and 

 even the fruit being injuriously afifected. He describes the injured 

 foliage as presenting a peculiar russet appearance on the under- 

 side, and as being somewhat curled, as though with drought. The 

 terminal shoots and the fruit is also attacked, being russetted 

 and cracked as a result of the pimctures of the mite. With serious 

 attacks.- the whole tree is said to have a brownish appearance, 

 giving the trouble the name "Rusty Leaf," by which it is known 

 in the Rogue River Valley, Oregon. We have never noticed such 

 severe attacks to the pear in British Columbia, but it would not 

 be surprising to find that such existed, so prevalent is the mite 

 throughout the fruit-growing sections. It would appear from the 

 foregoing that, though this pest is known to be prevalent through- 

 out the United States and Canada, it has never been regarded as 

 a serious enemy of apple foliage, and only locally as a serious pest 

 of pears. 



Through the summer of 1912 numerous specimens of apple 

 twigs were sent to the office of the Provincial Entomologist at 

 Vernon, disfigured in a curious way by brownish incrustations on 

 the bark of one and two-year-old wood. These injured areas were 

 generally more or less circular in form, though sometimes of an 

 irregular shape. A crack usually separated the healthy from the 

 diseased wood, and the epidermis was frequently ruptured. This 

 injury appeared to be most pronounced on wood of the Northern 

 Spy, though other varieties suffered to some extent. A careful 



