80 BRITISH OAK GALLS. 
in situ for some months firmly rooted in the twig, 
affording “an instance in this of what is frequently 
found to be the case, that when an inquiline lays its 
ege in an immature gall the growth of the gall is 
altered with the death of the original larva, and 
becomes pathological” (‘ Alternating Generations,’ 
. 44). 
Although the sexual generation is so plentiful, 
collaris is somewhat uncommon and does not appear 
to have been often found by the collector. 
Fie. 8.—Galls caused by Aphilothrix collaris. a. In situ, nat. size. 
sB. Enlarged x 4. c. Some leaf scales removed x 4. In part after 
Mayr. 
It is sometimes embedded in the leaf scales of A. 
fecundatriz. 
Aphilothrix corticis, Linn. 
(Plates XIX, XXII, div. A.) 
Cynips corticis, Hartig, Schenck., Kalt., Kirch., Thoms. ; Andricus 
corticis, Mayr, Cameron, Mosley ; Aphilothrix corticis, Adler, Mayr, 
Licht., Fitch, Ormerod. 
English name of gall.—‘ The Bark Gall.” 
Position of gall.—In the bark, in the rim of a callus, in axil of 
a branch. 
Manner of growth.—Glabrous, glossy, gregarious, conglome- 
rated, embedded. 
Colours.—Greenish-yellow, yellow suffused with pink, purple, 
brown. 
Average dimensions of a mature specimen. — Depth, 
10 mm.; breadth, 4 mm.; girth, 12 mm. 
May be sought during any month of the year. 
Growth is complete by the end of May. 
The typical condition of the gall is unilocular and unilarval. 
