74 



BEITISH OAK GALLS. 



here given. Care must be exercised when severing 

 the twig on which the}^ are growing. They are easily 

 dislodged, and having fallen to the ground are seldom 

 recoverable. In the cabinet also care must be taken 

 in handling them. They are usually quite solitary, 

 i. e. not more than one on a twig. Occasionally two 

 may be found near each other, and one twig I found 

 had three within a distance of 38 mm., each growing 

 from lateral buds. 



A large proportion of these galls will he found to 

 be quite empty. They are usually situated on the 



Fig. 7. — Galls caiised by Aphilothrix alhopunrtata, ilhistrating variability 

 in sitiTation, form, and marking, dele, ad nat. E.G. 



smallest twigs, sometimes in company with Audricus 

 solifarms. 



Its growth is rapid. AVhen the gall bursts through 

 the bud scales it is usually green in colour, with very 

 few or no spots upon it. The exterior consists of a 

 somewhat thick soft rind which shrinks in thickness 

 a great deal as the gall nears matuinty ; beneath this 

 are the cell walls, which are thin. The larval chamber 

 is large and occupies the entire cavity. As growth 

 proceeds cream-coloured or pale-yellow spots appear 

 in the rind, elliptical in shape, and extending in a 

 longitudinal direction. 



Numerous (15-20) furrows traversing the length of 



