134, . BRITISH OAK GALLS. 
Spathegaster verrucosus, Schlechtendal. 
Spathegaster verrucosa, Schltdl., Mayr, Fitch ; Dryophanta verru- 
cosa, Mayr; D. divisa, Cameron; Spathegaster verrucosus, Adler. 
English name of gall.—‘<The Red Wart Gall.” 
‘ Acca of gall.—On the leaf, and in axillary and terminal 
uds. 
Manner of growth.—Single, solitary, glabrous, glossy. 
Colours.—Greenish-yellow, pink, orange, red, reddish-brown. 
Average dimensions of a mature specimen.— Height, 
4mm.; girth, 6mm. 
May be sought during the months of April to June. 
Growth is complete by the end of May. 
The typical condition of the gall is unilocular and unilarval. 
The larva pupates in the gall. The imago emerges during 
May. 
Alternate agamic generation: Dryophanta divisa, Adler. 
On the surface of the gall, and generally near the 
apex, is a very small raised disc, or mamelon. Some 
galls have more than one. Under magnification it is 
seen to be a circular, or oval, elevation about 1 mm. 
in diameter, with.a depressed centre through which 
the imago eats its way out. This mamelon is some- 
what variable in colour, but when the gall is mature it 
assumes the reddish-brown hue of its surroundings. 
This gall develops upon three different situations. 
On the leaf from the end of the mid-rib, or the margin 
of the blade; at the termination of a twig, and, the 
axillary bud. This is explained by Adler as being due 
to the fact that D. divisa usually lays her eggs “in 
the rudimentary leaves.” <A slight deviation from the 
normal situation of the egg “ makes all the difference 
as to the positions of the gall. If the egg lies on the 
point of a leaf, the gall develops on that spot, and the 
full grown leaf bears a gall on its point; but if the 
egg lies deeper in the base of the leaf, the whole leaf 
surface is absorbed, and the gall rests directly on the 
shortened petiole. . . . the gall is merely substi- 
tuted for the leaf. When the egg is sunk still deeper 
into the axis of the bud the whole bud is absorbed in 
