33 
BRITISH GALLS 
caused by the presence of the larvae of Neurotevus tricolov. 
These galls are whitish, and covered with erect white hairs. 
They appear in June, and mature in July. The wasps 
emerge towards the end of that month, and prick the under 
surface of the leaf. The cupped spangle galls result 
(Fig. 4, b ; a magnified section is seen at Fig. 15). This 
gall is sometimes confused with that of N. laeviusculus , but 
there should be no difficulty in diagnosis if the sections are 
carefully compared. The wasps which emerge are known 
as Neurotevus fumipennis. Adler observes : “ They are very 
active little flies . . . continually running from side to 
side and flying from one shoot to another.” 
There is an attractive-looking gall which sometimes 
resembles a large ripe cherry, which appears in September 
on the under surface of Oak leaves (Plate XXII., Fig. 6). 
It is noteworthy that in 1910, which was not a favourable 
year for Oak galls, it was very abundant in many districts ; 
I noted it in enormous numbers on fallen leaves in Woolmer 
Forest. Its vivid tints are chiefly seen in bright summers; 
in the dismal summer of 1910 the great majority were 
yellowish-green. The colour is retained for a considerable 
time after the leaf has fallen and withered (Fig. 7). The 
wasp that emerges from it is the Dryophanta* folii (Fig. 8). 
It usually bores the canal for emergence some time before 
leaving its home, the outer skin of the gall remaining 
unbroken. It oviposits in the adventitious buds at the 
base of the trunk. According to Adler, only one egg is laid 
in each bud. The gall which results is small, 2 to 3 mm. 
long, of a beautiful dark violet colour, with a velvety 
appearance (Fig. 5). These galls appear about the end of 
April, and the wasps emerge towards the end of May. 
They are the Dvyophanta Taschenbevgi , and were at one time 
placed in the genus Spathegaster. 
Fig. 3 on the same plate shows the under surface of an 
Oak leaf with two striped pea galls and three common 
spangle galls. The striped pea gall is easily identified by 
* Dryophanta = Diplolepis of modern German authorities. 
