APHILOTHRIX RADICIS. 91 
also in the number, length, and depth of the furrows. 
Some examples are quite smooth, and but for the 
absence of the sharp pointed apex peculiar to the 
galls of Aid/ricus nudus, many small specimens might 
pass as that species. Yet mature galls of A. quadri- 
lineatus often show a papilla when dry; A. audus, 
however, never attains the same dimensions. 
Considerable indecision appears to have existed 
amongst writers as to the identity of this gall when it 
was first noticed on the continent. Its great varia- 
bility doubtless accounts for. this, and it also affords an 
explanation of its many synonyms, to which Schenck 
unnecessarily contributed five. 
Some years it appears in great profusion, clusters 
‘of eight and ten galls being frequently found on a cat- 
kin stalk. A very fine example I found in 1907 con- 
sisted of fifteen galls upon one stalk within a length of 
23 mm. 
“ Notwithstanding that this gall is very abundant it 
is by no means easy to rear the fly. From the 
majority of the galls parasites are usually obtained ; 
then the larva in a large number of instances does not 
develop into the imago for two years” (‘ Alternating 
Generations,’ p. 91). 
Aphilothrix radicis, Fabricius. 
(Plates XX VI, XXX, div. A.) 
Cynips radicis, Fabr., Hartig, Schenck, Kalt., Marshall ; Aphilo- 
thriz radicis, Mayr, Adler, Licht., Fitch, Walker, Miller ; Andricus 
radicis, Mayr, Cameron, Mosley. 
English name of gall.—‘ The Truffle Gall.” 
Position of gall.—On exposed roots, base of trunk and branches 
growing therefrom. ; 
Manner of growth.—Glabrous, sessile; solitary, conglomerated. 
Colours. --Cream, pink, orange, red, reddish-brown. 
Average dimensions of a mature specimen. — Height, 
45 mm.; length, 60 mm.; breadth, 40 mm. 
May be sought during any month of the year. 
Growth is complete by the end of the second autumn. — 
The typical condition of the gall is plurilocular, but unilarval. 
Usual number of cells, about sixty. 
