SPATHEUASTER BACCARUM. 129 



A feAv of the large outer leaf scales of the bucl 

 surround the base of the gall and assist in retaining 

 it in position. The greater part of the upper portion 

 of the gall is bare except for a few of the small inner 

 leaf scales which adhere to it. The gall does not fall 

 to the ground. The structure is of a vesiculate nature, 

 with thin, soft, and sappy walls. The interior forms 

 a large larval chamber. There may be two or three 

 larv^, each occupying a separate cell, but a larger 

 numl^er of cells generalh^ denotes the presence of 

 inquilines. The cells are oviform in shape, and 

 arranged perpendicularly on their own longitudinal 

 axis. They are large in comparison with the size of 

 the larva. The arrangement is sometimes indicated 

 on the exterior of the gall. 



The gall occupies about two-thirds of the bulk of 

 the bud. In shape it is an elongate ovoid, flattened 

 on the inner side for about four-fifths of its entire 

 length. It is foimd more plentifully on stub-oaks of 

 about fiv^e to seven years' growth, than on full grown 

 trees. 



Spathegaster baccarum, Linn. 

 (Plate LIII.) 



Cynijis Qnercus baccaruin, Linu. ; Sjjafhegaster interriiptor, 

 Hartig; 8. baccarum, Mayr, Fitch, Miiller, Adler, Marshall; 

 NeMroterus baccarum, Mayr ; N. Jenticularis, Cameron. 



English name of gall. — " The Currant Grall." 



Position of gall. — On the staniinate catkins, and on the leaves. 



Manner of growth. — Grlabrous, g-lossy, gregarious, succulent, 

 globular. 



Colours. — Pale green, greenish-yellow, pink, red, purple. 



Average dimensions of a mature specimen. — Ou catkin : 

 G-irth, 7 mm. On leaf : G-irth, 10 mm. 



May be sought during the months of May and June. 



Growth is complete by the end of Jime. 



The typical condition of the gall is unilocular and unilarval. 



The larva pupates in the gall. The imago emerges during 

 June. 







