4.64 
THE DICTIONARY 
OF GARDENING, 
Oak . 
and very juicy, are common, in May and June, on mg 
lower surfaces of leaves, and on catkins, where they 
ee > FIG. 707. OAK GALLS. 
A, Galls of Newroterus lenticularis (Oak S onie Galls)—1, On 
Lower Surface of Leaf ; 2, Removed from Leaf ; 3, Flat Section, 
showing round Chamber in centre where the Larva lives; 4, 
Transverse Section, in autumn, ee Form while still on 
the Leaf, with very small Chamber; Transverse Section 
of Gall in following spring, showing 8 Form and 
much larger Chamber. ree 4and 5 are about four times en- 
larged.) 
B, Galls of Spathegaster baccarum (Currant Galls of Oak)—1, Upper 
-” Surface of Leaf, showing Galls projecting through ; g” payor 
Surface of Leaf, showing three Galls, of which he Up noes 
cut through to show the Larval Chamber; 3, Male Catkin 
bearing Galls. (All the — are a little shialler than natural 
* 
) 
SaN like bunches of Currants (see Fig. 707). The insects 
(Spathegaster baccarum) are easily reared from these Galls, 
FIG. 708. OAK GALLS. 
A, 1, Galls of Dryophanta folii on Lower Surface of Oak Leaf, 
slightly smaller than natural size; 2, Transv erse Section, 
: showing Larval Chamber. 
B, 1, of Spathegaster Taschenbergi on a . Twig, natural 
very. thin. The; in May ug 
recorded PA AF Britain, are believed to be the Galls that complete 
wee cycle with those of folii. 
: ‘the latter are collected when fully mature, and pre- 
vented from becoming either too dry or mouldy. Dryo- 
Oak Galls—continued. 
phanta folii. produces a globular Gall on the backs of leaves. 
It may reach #in. in diameter, but the central chamber is 
small, the walls being thick, though soft and spongy. The 
surface becomes yellow and red. See Fig. 708. Dryo- 
phanta divisa also forms Galls on the lower surface of 
leaves, but the Galls are generally flattened, oval bodies, 
much smaller than the last-named, with harder, but 
thinner, walls. They are also more abundant. ugh- 
out the country. Oak Spangles are among the most 
curious of Oak Galls. They occur on leaves, almost always 
on the lower surface. Three kinds have been distin- 
guished in Britain, agreeing in being circular, about 
zin. across, and, while on the leaf, quite thin, though 
bearing a very slight prominence in the middle. The 
commonest is covered with rusty brown hairs; it often 
nearly covers leaves. See Fig. 707. Of the other two, 
one bears similar scattered hairs, and has the margin 
turned up; while the third is green or purple-red, and 
smooth. All are the work of insects belonging to the 
group Neuroterus, and which are named N. lenticularis, 
N. leviusculus, and N. fumipennis. Another species of 
this genus (N. numismatis) makes Silky Button Galls, 
so called from their resemblance to tiny, round, flattened 
A B 
FIG. 709. 
Oak GALLS. 
A, Galls of Neuroterus numismatis (Silky Button Galls of Oak)— 
1, Lower Surface of Leaf, bearing many, about natural size; 
2, Gall showing the depressed Surface, enlarged; 3, Gali 
seen from the side ; 4, Gall in Section, showing small central 
Chamber for Larva, hollow Border cut through at side, 
and short Footstalk. 
B, 1, Three Galls of Spathegaster Stent (Blister Gals of Oak 
Leaves) i in a Leaf, natural size; 2, Transverse Section of Leaf, 
with Gall, showing very small Larval Chamber. 
buttons, covered with brown silk threads (see Fig. 709). 
These Galls are often groa in myriads on the lower 
surface of the leaves, as, in some cases, to cover 
it almost entirely in autumn. Vet another Gall, of 
very frequent occurrence, is so inconspicuous as to be 
easily overlooked in the leaves, in which, during June, 
it looks like a mere low blister, about zin. across (see 
Fig. 709). The insects reared from these Galls have 
been named Spathegaster vesicatriz, This may be called 
the Oak Blister Gall. 
In acorns, at times, Galls are to be found in the 
seed, though the outside of the acorn shows no sign 
of insect work. The interior is broken up by nume- 
rous small oval spaces, in each of which lives a small 
larva of the Gall-maker (Andricus glandiwm). 
These brief notes must suffice for the more common 
forms of Oak Galls; and attention must now be directed 
for a little to certain points in the life of the Gall-makers— 
points which, for a considerable time, seemed to defy ex- 
planation, but which are gradually emerging into the light, 
thanks to the careful experiments and observations of 
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