34 INSECT-GALLS OF THE VICINITY OF NEW YORK CITY 



accumulated aborted leaves, ^ to J in. long. Caused by the arrest of the side 

 branches. Inside, at the base, is a hollow space in which the larva li\-es. On 

 stalk of goldenrod {Solidago altissima) . Singly or in numbers. Common. 



75. Goldenrod Ball Gall {Trypeta solidaginis Fitch). — Globtilar, ball-like 

 and about i in. in diameter. Pithy inside with a rounded cell in the center. 

 On the main stalk of goldenrod. Common. 



HEMIPTERA (Bugs). 



Family Psyllid^ (Jumping Plant-lice). 



The insects belonging to this family subsist entirely upon 

 the juices of plants. They are comparatively small, measuring 

 from 1 to y\ inch in length. Their hind legs are formed for 

 jumping. 



76. Hackberry Petiole Gall {Pachypsylla vcnusta Osten Sacken). — Globular 

 or irregularlv rounded. Consists of a thin outer shell with several compart- 

 ments inside. On petiole of the leaf of hackberry {Celtis occidentalis) . Not 

 common. 



