ANDRICUS INFLATOR. 63 
small trees, but more generally on the lower than the 
upper branches; very rarely on scrub-oaks of less than 
three years’ growth. | 
Andricus inflator, Hartig. 
(Plate XI.) 
Andricus inflator, Adler, Miller, Mayr, Mosley, Fitch, Cameron ; 
Cynips inflator, Thoms. 
English name of gall.— The Twig Gall.’ 
Position of gall.—At the extremity of twig or shoot. 
Manner of growth.—Single, glabrous, sessile, glossy. 
Colours.—Green, dark green, brown, dark brown. 
Average dimensions of a mature specimen. — Height, 
15 mm.: breadth, 10 mm.; girth, 30 mm. 
May be sought during any month of the year. 
‘Growth is complete by the end of September. 
The typical condition of the gall is bilocular, but unilarval. 
The larva pupates in the gall. The imago emerges during 
June to August. 
Parasites, Nos. 21, 56, 83, 87, 154. Inquiline, No. 110. 
Alternate agamic generation: Aphilothriz globult, Hartig. 
The gall results from the gall-wasp laying its egg in 
the axis of the terminal bud. When the bud develops 
in the spring the apical portion remains whitish for a 
long while. 
In all stages of development the gall is easily 
recognisable. 
In some districts this gall is exceedingly abundant, 
and many oak bushes have a very great number of the 
galls on the twigs; but there 1s not always a pro- 
portionate abundance of the alternate generation in 
the succeeding autumn. 
The egg is laid in the axis of a bud during September 
or October by Aphilothrix globuli. No gall-growth 
takes place until the following spring, when the larva 
hatches. Rapid swelling of the tissues then begins, 
resulting in an enormously thickened and stunted 
shoot. During the summer leaves and occasionally 
short twigs grow from the exterior of the gall. In 
