92 . «THE CANADIAN ENTOMOLOGIST. 
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The relationship of these species to any known species was only 
inferentially established. It is true that the leaves of several oaks on 
which I found one species very abundant, were almost all covered with 
galls of C. g. futilis, O. S., but the females of this speciés were not so 
large as my new bud stinging species. 
I have, for the past three years, carefully examined the buds of Q. 
ilicifolia, hoping to find the producer of C. g. operator at work, but without 
success, till this week, when I found no less than thirty gall flies ovi- 
positing in the buds of this oak. 
That they really are the producers of these galls needs no further 
proof than I now give. The insect C. g. operator is distinguished from all 
our other species by the projection of the ovipositor above the dorsum. 
In this respect it resembles the several species of guest gall flies that 
infest almost all our species of galls. It has, however, the neuration of 
the true gall flies. In size my insects are considerably larger than C. g. 
operator, but in form, color, neuration of the wings, and, above all, in the 
peculiar form and position of the sheath of the ovipositor, they are like 
this species. 
Few will doubt their identity; but to make ‘ assurance doubly sure,” 
I hope some one will be so fortunate as to raise gall flies from these acorn 
galls, when a comparison with mine will settle the question whether this 
particular species (C. g. operator) is double brooded or not. 
I wish (if my article is not already too long) to state a few other facts 
and to show their bearing upon the history of these interesting insects. 
There stands not far from my house a small oak tree, Q. bicolor, which 
js almost ruined by the ravages of a species of gall fly, which closely 
resemb'es and may be identical with C. g. dofatus, Bassett. Every summer 
the leaves of this tree are so injured by the galls that scarcely one perfect 
one can be found on the tree. The petioles and midveins are enlarged to 
the size of one’s finger, and the blade shrivels up or remains undeveloped, 
and each gall contains a large number of insects which come out in June. 
I have reared many thousands of these gall flies and find them of both 
sexes—about equally divided. 
Late in the summer another form of gall appears, this time on the ends 
of the small branches, and the insects remain in these, in the imago, 
through the winter. I have reared not less than fifteen thousand of these 
gall flies and al/ are females, and they cannot be distinguished from the 
