INSECT-GALLS OF THE VICIPnTY OF NEW YORK CITY 13 



cells. About i to i^ in. in diameter. On branches of the pin oak {Quercus 

 paliistris). Exceedingly common throughout the year. 



20. Oak Knot Gall {Andricus punctatus Bass.). — Shape similar to the 

 preceding gall, but without the horn-Hke protuberances. Sometimes found 

 singly, but often a number may be seen, in greater or less proximity, on the 

 same branch. On black jack oak {Quercus marylandica), scarlet oak {Quercus 

 coccinea) and rarely on scrub oak {Quercus nana). Common. 



■ ' -:>%" -J^f-^AiX'^- -^ 





21. Oak Seed Gall {Andricus seminator Harr.). — Composed of a woolly 

 substance and irregularly rounded. Inside are numerous bodies adher- 

 ing to the twig and resembling canary seeds. About i to if in. in diameter. 

 Pure white sometimes tinged with red; toward the middle of the summer it 

 assumes a rusty brown color and gradually drops off the twig. On twigs of 

 white oak {Quercus alba). Common. 



Oak Wart Gall {Andricus fuiilis Osten Sacken). — Rounded, somewhat 



