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 OUgotrophus annuUpes (Plate IX,, 

 Fig, 5, magnified). Like numerous other galls, those of 

 O. annuUpes axe 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 1 910 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 191 1, 

 This gall stands up on the leaf like a little tube, about 

 5 mm, high and 2 mm. in diameter (Plate IX., Fig, i), 

 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 lo mm, high, 



