INSECT-GALLS OF THE VICINITY OF NEW YORK CITY 27 



globular, onion-shaped and covered with pubescence which is pale when the 

 gall is young and growing, and becomes rust-colored when mature. Inside it 

 is hollow and contains a single larva. On the under surface of the leaves 

 of different kinds of hickory. Sometimes they cover the entire under surface 

 of the leaf. Very abundant. 



57. Hickory Seed Gall {Cecidomyia caryacola Osten Sacken). — Smooth, 

 elongated, rounded, with the tip produced into a point. Pale green. In 

 clusters on the under surface of leaves of different kinds of hickory. Common. 



58. Hickory Tube Gall {Cecidomyia tiibicola Osten Sacken). — Narrow, 

 cylindrical, tube-like, inserted in a small protuberance on the leaf, breaking 

 off very easily. Green when immature; black when fully grown. On under 

 surface of the leaves of different kinds of hickory. Common. 



