14 INSECT-GALLS OF THE VICINITY OF NEW YORK CITY 



flattened, projecting on both sides of the leaf. Inside are two or three seed- 

 like, oblong kernels, kept in position by white filaments. Pale green. In 

 numbers on leaves of white oak {Querciis alba). Very common. 



23. Oak Nipple Gall {Andriais papillatus Osten Sacken). — Rounded and 

 somewhat nipple-shaped. Projects on both sides of the leaf and is enclosed 

 in a reddish areola on the under side of the leaf. This is a very characteristic 

 feature and distinguishes it from the preceding species. Inside are two or three 

 kernels each containing a single larva. In numbers on leaves of chestnut oak 

 {Quercus prinus). Common. 



24. Scrub Oak Club Gall {Andricus sitmlis Bass.). — Club-shaped, blunt at 

 ape.x, which is generally turned to one side. Length ^ to i in. Hard and 

 woody, with a few leaves growing from it in summer. On terminal twigs of 

 scrub oak {Quercus nana). Not common. 



