86 
the European leaf mite—a supposition in favor of which I shall 
adduce some further proof. It is worthy of remark that upon even 
the worst infested plants at Normal the youngest or smallest leaves 
were usually quite uninjured. 
This same mite was subsequently found by my assistant, Mr. 
Gfarman, upon wild grapes in Southern Illinois, producing upon the 
leaves there an identical deformity. It seems extremely improbable 
that the European species could have been conveyed to this coun¬ 
try and have become so wide spread as to reach the wild vines in 
forests without having hitherto attracted attention in vineyards; and 
I am consequently inclined to believe that the vineyard mite of 
America has spread in the reverse direction that it is a native 
species probably belonging to our wild vines, and has from them 
entered our vineyards. 
Indeed microscopic study of the mite itself discovers some minor 
points in which it disagrees with the figures and descriptions of the 
European Phytoptus vitis. The body is less strictly cylindrical, 
and the lateral branches of the tarsal plume are less numerous. 
The descriptions of the European forms by Landois and Briosi are 
however so inconsistent with each other (the original description of 
Landois giving, for example, one hundred and twenty as the num¬ 
ber of abdominal rings, and that of Briosi from sixty to sixty-six) 
that it is impossible to make an intelligent comparison of our form 
with theirs without authentic specimens. I have consequently treated 
our species under the old specific name. 
The specimens examined by me varied in length from .45 to .64 
of an inch, and in greatest diameter from .014 to .019 of an inch. 
The body is broadest immediately behind the legs and thence tapers 
regularly, as seen from above, to the posterior extremity. The rings 
number about sixty-five; the tarsal plume has certainly but four 
lateral filaments, and not five, as reported for Phytoptus vitis by both 
Briosi and Landois. 
Plant diseases due to Phytopti have hitherto been controlled only 
by the use of sulphur, the method being described in my Eirst he- 
port, page 142. As such applications are already in use for fungus 
affections of the grape leaf, they will doubtless be found conveniently 
applicable for Phytopti in the vineyard. 
