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NATURE-STUDY REVIEW [12:5— May, 1916 



being pointed and others variously sculptured and colored. (Fig- 

 ures s, 6, 7, 8,). 



Twig and bud galls are generally globular in form or approxi- 

 mately so. They are sometimes singly placed, but very often 



occur in grapelike clusters. 

 The oak fig gall consists 

 of several individual galls 

 grouped in a tightly fit- 

 ting mass; the willow or 

 potato gall looks very much 

 like an old dried up speci- 

 men of the potato, and the 

 blackberry seed gall is easily 

 mistaken for a cluster of 

 woody seeds. 



Fig. 6. Wild Cherry Pouch Gall. 



Stem-like, expanding at the end into a pouch- 

 like sack. About two-fifths in. long. Hollow, 

 with an exit on under side of leaf. Green 

 or red.tl'Jn numbers on leaf of wild cherry. 

 (After ]Beutenmuller) . 



Classification of Insect Galls 



The classification of galls is rather difficult and four methods 

 that have been suggested are here given. 

 I. Simple and Compound Galls. 



i . Simple galls : those galls that are limited to a single plant 

 organ. 



Fig. 7. Maple Spot Gall. 



Eye-like, circular, flat. Light yellow, with a red cen- 

 tral dot, or entirely green or yellow. In numbers on the 

 leaves., of red maple. (After Beutenmuller). 



