THE ENTOMOLOGIST. 195 
a moderately thin but hard wall, consisting of an outer layer, 
originally green in colour, but afterwards brown, covering 
the thin, brownish yellow, oviform inner gall. Most of the 
galls have fallen by the beginning. of November; but in the 
following spring we often meet with leaves that have galls 
at their basal half, and have been prevented from falling 
by the thickening of the midrib. We have not been 
successful in breeding the gall-maker as yet. However, I 
have extracted a dead specimen from a gall.—G. L. Mayr. 
The description of this specimen—a female—is given in a 
footnote. The gall is figured by both Malpighi and Réaumur. 
It does not occur in Britain. From the galls of this species, 
and from N. ostreus galls, Dr. Mayr bred a new Synergus,— 
S. tristis, Mayr,—a species closely allied to S. nervosus and 
S. Tscheki. It occurred in the spring of the second year, as 
do also the other inquilines,—Synergus vulgaris, Hart., and 
Ceroptres arator, Hurt.— FE. A. Fitch. 
56. Andricus curvator, Hart. (A. per- Fig. 56. 
Sfoliatus, Schk., A. dimidiatus, Schk., 
G.avillaris, Bart.).—This very common 
gall appears by the end of April, when 
the leaves of Quercus sessiliflora, Q. pe- 
dunculata, and rarely those of Q. pubes- 
cens, begin to develop themselves. It 
appears on both sides of the leaf, often 
causing it to curl up, and looks like a 
green spherical swelling, of about the 
size of a pea. It often occurs at the 
margin of the leaf, when we find on 
the outer or exposed side a more or 
less distinct furrow, extending in a 
curve from the centre of the lower side 
to that of the upper side. This furrow 4. curvAtor (i in section). 
is absent in those galls which grow in 
the middle of the leaf, and are surrounded by the parenchyma 
(A. perfoliatus). This gall is bare above, and covered with 
fine, short, sparse hairs below; only when on Q. pubescens 
is the gall piliferous on both sides. It is somewhat cartila- 
ginous, and has a moderately thin wall enclosing a large 
cavity, to the sides of which the small, brown, thin-walled inner 
gall, which is scarcely the size of hemp-seed, loosely adheres. 
