THE AMERICAN MUSEUM JOURNAL 



17. Oak Spindle Gall {Amphibolips ccelebs Osten Sacken). — Elongated, 

 spindle-shapc, soft and green. Contains a kernel held in position by radiating 

 fibers. Length li in. On leaf of red oak {Qiicn-ns rubra). Not eommon. 



18. Acorn Pium Gall (Amphibolips prnniis Walsh). — Globular, somewhat 

 wrinkled or smooth, fleshy but solid; resembles a plum or cherry. About \ to 

 I in. in diameter. Bright crimson outside, pinkish inside and shading to 

 yellow towards the center. In the center is a single cell in which the lar\-a li\-es. 

 On cup of acorn of red oak {Quercus rubra). August and September. Some- 

 times rather common. 



19. Horned Knot Oak Gall {Atidriciis coniigcnis Osten Sacken).— Irregularly 

 globular with many horn-like protuberances through which the gall-flies escape. 

 Very hard and woody. Color of the branch. Inside brown with many lar\-al 



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