98 BRITISH OAK GALLS. 
When the gall is mature the rind dries, cracks, and 
falls away, leaving the yellowish-brown inner layer. 
If the gall is gathered before maturity, the rind will 
dry and adhere as a thin skin, so closely as to show 
the striz beneath it. ; 
Small birds, principally tits, break open the galls 
in winter time, and devour the inhabitants. 
This gall seldom occurs singly, 7.¢. only one on a 
shoot or twig; it is characterised by the large numbers 
clustered together—seventy or more within a linear 
distance of 7 cm. 
When a great many are crowded on a shoot, they 
penetrate the zylem so deeply that further growth of 
Fie. 10.—Galls caused by Aphilothriz Sieboldi illustrating typical shapes 
and situations. Nat. size, dele. ad nat. E.C. 
the shoot is prevented. It does not, however, decay, 
but will remain attached for some time, and, frequently 
shoots may be found bearing new galls near to those 
of one and two previous years. 
This gall received its specific name after M. von 
Siebold, who was one of the earliest to find the galls 
at Dantzig and Frieburg. 
Biorhiza aptera, Fabricius. 
(Plates XXXI to. XXXTIT.) 
Cynips quercus terminalis, Fabr.; Teras terminalis, Marshall ; 
Biorhiza terminalis, Mayr; Cameron. Biorhiza aptera, Adler ; 
Mayr; Miller; Marshall. Cynips aptera, Fabr. 
English name of gall.— The Root Gall.” 
Position of gall.—On roots and rootlets. 
Manner of growth.—Glabrous, sessile, gregarious, coalescent. 
Colours.—Pink, yellowish-brown, red, reddish-brown, chocolate 
brown. 
