126 
PROCEEDINGS OF THE PERTHSHIRE SOCIETY OF NATURAL SCIENCE. 
remains are often to be seen on the trees for several years. 
Andricus ivflator Hart, is one of our rarer Scottish 
gall-makers; but its galls have been found by Mr Cameron 
near Glasgow, and by myself on Deeside, in the month of 
July. They appear as terminal swellings on the young 
twigs. On section this swelling is found to enclose a cup¬ 
shaped cavity, in the bottom of which lies a tiny egg-shaped 
brown body, with a wall hardly thicker than a sheet of 
paper. This inner body is attached to the cup only at one 
point, and is very easily separated from it when mature, 
so as to lie loose in the comparatively large hollow of 
the cup. The larva lives inside this inner gall. The cup 
is closed above only by a thin membrane. The insects 
emerge in July, and are of both sexes. The galls of this 
insect are often simulated rather closely by a much more 
common gall, that of A. curvator Hart., when these 
occur, as they do at times, in the twigs. As the latter 
galls are far more commonly found on the leaves I shall 
defer saying anything more about them for the present. 
We come next to the galls formed upon the leaves, 
either on the lamina, the leafstalk, the midrib, or the leaf- 
veins. Of these, numerous species have been recorded 
from Scotland, some of them being large and showy, 
others small and inconspicuous. 
Dryophanta folii L. is the maker of the large round 
galls, resembling marbles in size and form, that are com¬ 
mon on Kinnoull Hill and elsewhere in Perthshire, and 
which I have also found near Forres, in autumn, on the 
backs of oak leaves. From their size they cannot be 
mistaken for any galls but those of Cynips Koliari ; and 
from the latter they are easily distinguished by their 
situation (on the leaves), their bright red or yellow 
colour, and their softness. The walls are very thick, 
and spongy in texture; and show no true inner gall. The 
insects emerge during winter from the galls, and are 
asexual. 
Dryophanta longiventris Hart, forms galls resembling 
the last in general appearance, but smaller, being the size 
of rather large peas, and characterized by their colour 
being red, with broad yellow bands, which may be raised 
above the level of the rest of the gall. These bands sur¬ 
round the gall. In texture and structure this gall 
much resembles the last. The insects are said to emerge 
in November, and are asexual. Mr Cameron records 
these galls as rare, at Cadder, near Glasgow. 
Dryophanta divisa Hart., unlike the last, is one of the 
most abundant of gall-makers. We may sometimes see 
small oaks with a dozen or more of them on almost every 
leaf, and it is seldom that only one occurs on a leaf. They 
are restricted to the lower surface, where they are attached 
by a point to the midrib or to the side-veins. The form is 
that of a sphere considerably flattened, and often some¬ 
what irregular. The surface is smooth and shining, or 
has small flattened warts scattered over it. Its colour is 
pale yellowish-brown, often with one side red. The wall 
is not relatively very thick, and it is much more compact 
than in the allied species. In size the gall seldom exceeds 
jj-inch in diameter. The insects emerge in June, and are 
asexual. The galls form in autumn. 
Neuroterus lenticularis 01. is the maker of the “oak- 
spangle ” galls so universally abundant wherever oaks are 
to be found in the wild state. They seldom, indeed hardly 
ever, are to be seen on the upper surface of the leaves, 
though frequently there may be scores crowded as closely 
as they can lie on the lower surface, so closely that they 
overlap one another on all sides. Where they have room 
to assume their characteristic form they are seen to be flat 
or lens-shaped from above downwards, and circular when 
looked at from above, with a slight elevation towards the 
middle. I have never seen them exceed £-inch in width by 
about half as much in thickness while on the leaf. The 
surface is rusty red owing to the existence of tufts of 
stellate short hairs, and the side next the leaf is smooth. 
These galls appear in July or August. They fall to the 
ground shortly before the leaves themselves fall, and lie 
concealed amidst the fallen leaves during the winter. 
While on the leaf, the central cavity, in which the larva 
lives, remains very small; but during the winter it enlarges, 
and the gall becomes highly convex. The insects pass 
through their metamorphoses while the galls are on the 
ground, and emerge in the following spring. They are 
asexual. 
Neuroterus fumipennis Hart, makes galls very similar 
in form to those just described. They may easily be 
recognised by being smooth, with little trace of hairs, 
and pale green, or red if on the upper surface of the 
leaf, though this is not their usual situation. Generally 
there are not more than six or seven on a leaf, and very 
seldom are two of the galls in contact. They pass through 
a similar development with the former, the insects emerg¬ 
ing in spring, and being asexual. These galls are not very 
general in Scotland, and seem almost restricted to the 
south side of the Grampians. 
Neuroterus numismatis 01. is very common in most 
parts of Scotland, though in a few localities it seems rare 
or local. The galls are scattered, or may be crowded in 
scores, on the back of the leaves. They are of very peculiar 
appearance, and have received the name of “silky-button 
galls” from their singular resemblance to the small silk 
buttons, with a central hollow at the top, so commonly 
