1 6 INSECT-GALLS OF THE VICINITY OF NEW YORK CITY 



with an oblong kernel inside held in position by radiating fibers. Green and 

 soft in spring; brown and brittle later in the season. Varies from ^ to ^ in. in 

 diameter. On leaves of red oak {Quercus rubra). Rather common. 



28. Oak Petiole Gall (Andricus petiolicola Bass.). — Rounded or club-shaped, 

 hard and woody, with many cells inside. About f in. in diameter. Green in 

 summer; brown in winter. On petiole, base or midrib of leaf of white oak 

 {Qtiercus alba), chestnut oak {Quercus prinus), swamp white oak {Quercus 

 platanoides) and post oak {Quercus minor). Common. 



29. Oak Wool Gall {Andricus lana Fitch). — Very much resembles a mass 

 of wool about f in. long. White or bufi colored, inside with many small, 

 bright chestnut colored, seed-like capsules, crowded together and attached by 

 their lower ends to the vein of the leaf. On the under side of ribs of leaf of 

 white oak {Quercus alba). Common. 



