INSECT-GALLS OF THE VICINITY OF NEW YORK CITY 



77. Hackberry Nodule Gall {Pacliypsylla celtidts-gemma Riley). — Variable in 

 size and in shape. Bud-like and looking as if formed by the agglomeration of a 

 number of rounded nodules. Hard and woody, with a number of cells inside. 

 On branches of hackberry {Celtis occidentalis) . It is a deformation of the 

 young bud. Common. 



78. Hackberry Blister Gall {Pachypsylla celtidis-vesiculum, Riley). — Circu- 

 lar, flat and blister-like. Convex on the under side with a small nipple in 

 the middle. Green. In numbers on leaf .of hackberry {Celtis occidentalis). 

 Common. 



79. Hackberry Nipple Gall {Pachypsylla celtidis-mamnia Riley). — Repre- 



121 



