Che pear-leaf blister (Figs. 00 and 00,) is the result of a disease 
ich is widely known, but not commonly understood to be due to 
5 ravages of mites. Such is, however, the fact, as is now well 
Dwn to foreign horticulturists. Recently, Prof. T. J. Burrill has 
covered mites in blistered pear leaves in this State, and tells us 
id they are identical with the European Phytoptus pyri*, a species 
ich he thinks has been introduced with imported pear trees. In 
1 account of this malady, which he has kindly furnished me (see 
ytoptus pyri, Scheuten, at the end of this paper), he says, regard- 
i the effect of this mite’s work upon the pear trees : 
i* Trees are not killed outright, but much injury is done by this 
j rk upon the leaves; sometimes, also, the much more deadly 
| ight ’ shoots from the minute wounds made by the mites. A tree 
[j—-- 
: Since the above was written, I chanced upon a reference to the work of this mite on 
pear trees, in the report for 1872 of the U. S. Entomologist. 
W 
Figs. 24 and 25. Leaves of the pear tree, showing two stages of the galls pro 
duced by Phytoptus pyri (after Sorauorj. H. Garman, del. 
