72 
troduced into Devonshire, where they first appeared in Britain, 
about forty years ago. Since that time they have spread north- 
wards, and are now common in various places in the southern 
half of Scotland. Dr. Vice told me, in April, 1875, that he had 
seen specimens a few days before on a small tree at Culter ; and 
Mr. Taylor has given me two galls found by him this year at 
Kingcausie. I have myself seen them abundant at Murtle, and 
also found one at Parkhill. They are very like marbles, scattered 
singly, or in small groups, on the younger twigs, 4-1 inch in 
diameter, smooth, or bearing a few warty knobs. They are soft 
at first (till September), but gradually become harder, and those 
gathered in winter retain their form perfectly. On section, they 
are found to consist of a thin, hard rind, enclosing a thick layer 
of rather loose and soft tissue, closely united to a more compact 
but undefined cell-wall; the central cell is small. 
c. Galls of Aphilothriz gemme L, (Cynips fecundatrix Hart)—‘ Arti~ 
choke galls’, They resemble miniature artichokes in appearance 
(1 X 2 inch), as they are composed of an acorn cup, the scales of 
which are closely imbricate, enlarged, and covered with short, 
pale hairs, but have brown margins. In the centre is an inner 
gall, about } inch long, in which is a rather large larval-celi, 
The inner gall drops to the ground in autumn, and the insect 
emerges next year; the outer gall remains on the branch in a 
withered state often for more than ayear. These galls are com- 
mon at Banchory, near Ballater, at Parkhill, and at Inverurie. 
D. Galls of Andricus terminalis, Fabr. They are generally known as | 
‘Oak-apples,’ on account of their forming masses from } inch te 
3 inches across, covered when fresh with smooth soft skin yellow- 
ish in colour, save on the side exposed to the sun, where it is red. 
They are usually situated on the ends of the branches (less fre- 
quently they are axillary, and are small); they are irregularly 
rounded or oval. The skin is very thin, and covers a fleshy mass, 
towards the centre of which there are many well-defined small 
oval larval-cells, formed of hard, compact tissue. The galls appear. 
in early summer, but remain on the branches for a year or more. 
Old galls consist only of the mass of cells, the soft parts having 
fallen away. They are very subject to attacks of parasites and 
inquilines. They occur abundantly at Banchory, and near Ballater. 
E. Galls of Andricus inflator Hart. They are terminal (rarely axillary), 
swellings on the young branches, ovate, about + X + inch, smooth 
externally, or with leaf-scales, or small leaves, attached to them, 
and have a small hole at the blunt apex, closed by a thin membrane. 
The walls are thin, and enclose a large cavity, at the bottom of 
which is a dark brown very thin walled ovate inner gall (about 
iz X vs inch), in which lives the larva. These galls I found 
plentiful on an oakbush near Ballater. Their formation, as Herr 
Mayr suggests, is owing to the female depositing an egg in the 
terminal bud, whereby the bud is checked in its growth, while 
the surrounding parts grow up and cover it. 
Sub-div., Leaf Galls. 
F. Galls of Biorhiza renum, Hart. They are attached to the side-veins 
on the lower surface of the leaf (usually in pairs, one on each side 
of the vein), usually many occurring on a leaf. They appear in 
September, and at first are very small (? — ~ fe = } and kidney- 
shaped. In October they swell to three or four times their former 
