GALLS CAUSED BY GALL-WASPS 



41 



May. It is greenish at first, becoming brown at maturity, 

 and is covered with erect whitish hjurs. It much resembles 

 the gall of Andricus amenti (whose agamic generation is 

 unknown), but is larger, stouter, not so pointed, and has 

 longer hair. 



Andricus pilosus appears in the middle of June. The 

 female attacks the axillary buds, giving rise to the arti- 

 choke or hop gall. This gall occurs chiefly on young 

 Oaks, often in large numbers on saplings. The scales of 

 the leaf bud become greatly hypertrophied, and the true 

 gall lies in their midst. It is small, pear-shaped, green at 

 first, brown at maturity, becoming hard and woody. In its 



4 5 



Fig. 4 — Galls on Buds of the Common Oak caused by the 



PRESENCE OF THE Larvae OF Cynips KollaH. (1/2.) 

 Fig. 5^-Galls caused by the presence of the Larvae of 



Andricus circulans in a Turkey Oak Bud. (2/1.) 



early state it is joined to the bud, later it becomes detached 

 and falls to the ground. The wasp (Andricus fecundator) 

 may emerge in spring, but in many cases the larva lives 

 within its wooden prison for three, or even four, years 

 before metamorphosis takes place. Some, for unexplained 

 reasons, never change. The inquilines and parasites are 

 not numerous ; lists have been given by Cameron and 

 others. The moth Carpocapsa Juliana is found commonly 

 in these galls. 



The very familiar marble gall is situated on a terminal 

 or lateral bud, and is about the size of a marble when 

 fuU grown. It is yellowish at first, becoming brown at 



