HO MO PT ERA 



427 



young of the migrants, the third generation, feed a short time and 

 then settle close to the leaf -buds, where they hibernate; the last in- 



Fig. 498. — The spiny witch-hazel gall: a, mature gall; b, section of gall. (From 

 Pergande.) 



star of this generation resembles a coccid (Fig. 499). The fourth 

 generation is produced early in the spring ; the young of this genera- 

 tion move to the young and tender leaves of the birch, which, as a 



Fig. 499. — Hamamelistes' spinosus, last instar of the third generation, much 

 enlarged: a, dorsal view; b, lateral view; c, ventral view; d, antenna; ^ 

 /, g, legs. (From Pergande.) 



result of the attack, become corrugated, the upper surface bulging 

 out between the veins, and the folds closing up below. In these 



