NORTH AMERICAN IIYMENOPTERA. 



Div. I. — Galh on the leaves. 



12/ 



-Galls not intimately connected with the substance of the leaf, 

 generally fastened by a small portion of their sur- 

 face and which can be removed without carrying a 

 portion of the leaf with them. 

 o._Globular galls with a kernel in the centre kept in position 

 by a softer substance, spongy, fibrous or succulent ; 

 or by filaments radiating from it to the shell ; all 

 monothalamous. 

 -]-._Kernel kept in position by a dry, spongy substance. 

 Shell thick . AmphiboUps spongifica O. S. (Q,. tinctoria). 

 Shell thin . AmphiboUps confluens Harris (Q. rubra). 

 Surface glossy . AmphiboUps coccinece 0. S. (Q. coccinea). 

 Surface spiny . AmphiboUps spinosa Ashm. (Q. laurifolia). 

 -j-j-._Kernel kept in position by delicate, radiating filaments. 

 Large, shell thin ; surface glossy . AmphiboUps inauis 0. S. 



(Q. rubra, Q. coccinea). 

 Large, shell thin ; surface mottled . Holcaspis eentricola O. S. 



(Q. obtusiloba). 

 Small, smooth, brown . Dryophanta poUta Bass. ((^ obtusi- 

 loba) ; Andricus bella Bass, (unknown oak). 

 Small, smooth, yellow . Andricus femomtus Ashm. (Q. 



laurifolia)- 

 |-|-|-._Kernel kept in position by a soft, succulent substance ; 

 galls resembling green grapes . AmphiboUps sndpta 

 Bass. (Q. rubra, Q. tinctoria) ; A. racemaria Ashm. 

 (Q. laurifolia). 

 -j-j-j-|-._Kernel surrounded by a dense, cellular substance. 

 Galls generally in clusters; shell smooth . Andricus virens 



Ashm. (Q. virens). 

 Bell shaped . Acraspis vaccinu Ashm. (Q. obtusih)ba). 

 Small, pubescent . Cynipsf decidua Bass. (Q. rubra). 

 Minute, pubescent . Dryophanta ignota (Q. bicolor). 

 aa.-Hard, globular, or irregularly rounded galls, without a dis- 

 tinct kernel ; one, two or more celled, the surface 

 smooth or netted or fissured like a strawberry. 

 One celled, without spines . Biorhiza JuHa Bass. (Q. montaua) ; 



^cra8joispeza»iac/iotrft'.^ O. S. 'vQ. alba). 

 One celled, with spines . Cynips echinus 0. S. (Q. agntolia). 



