70 
BRITISH GALLS 
on the inferior side of the leaf. They are pale green at 
first (Fig. 6), becoming reddish-brown or purple at maturity. 
Each gall contains an orange-coloured larva, which pupates 
in it (Fig. 8, section; Fig. 9, pupa) or in the earth. It is 
sometimes plurilocular, containing numerous cells. It is 
not common in Britain, but has been recorded from several 
counties. 
The little hairy tubular galls on the upper surface of 
Beech leaves are caused by Oligotrophus annulipes (Plate IX., 
Fig. 5, magnified). Like numerous other galls, those of 
O. annulipes are extraordinarily abundant in certain years, 
and uncommon or rare in others. In the autumn of 1906 
they were very numerous in the Haslemere district, also in 
the Beech woods adjoining Heyshott Down, and elsewhere 
on the South Downs. 
In 1910 they were so scarce that we experienced some 
difficulty in finding any for exhibition at the Haslemere 
Museum, and they were almost equally scarce in 1911. 
This gall stands up on the leaf like a little tube, about 
5 mm. high and 2 mm. in diameter (Plate IX., Fig. 1), 
usually on or close to the midrib. It is yellowish-green, 
with Irregularly tuberculated surface at the apex, and is 
covered with greenish or purplish-brown hairs. Its position 
is indicated on the lower surface of the leaf by a slight 
circular elevation (Fig. 2) with a reddish or purplish tint 
in the centre. A magnified section is shown in Fig. 4. 
The interior is rough and fibrous, and contains a white 
larva. The gall falls away at maturity, leaving a circular 
scar on the leaf. The larva pupates in the earth. The 
best time to find these galls is in October, when the leaves 
are falling. Leaves bearing them will be quickly recognized 
by the conspicuous patch of green surrounding the galls 
when the remainder of the leaf is brown (Fig. 3). The oasis 
is usually margined with yellow. 
The galls caused by Mikiola fagi occupy a somewhat 
similar position on Beech leaves, but are easily known by 
their more ovoid form, larger dimensions—8 to 10 mm. high, 
