PERGANDE NORTH AMERICAN PHYLLOXERIN^. 21 7 



14. Subglobose ; about equally prominent above and beneath ; without a 



nipple ; opening in a transverse slit Ph. c.-scissa Riley. 



15. Subglobose, somewhat more prominent above than beneath ; without 



a nipple ; the orifice an elongate slit Ph. c.-globuli Walsh. 



It). Subglobose ; about equally prominent on both sides ; conical 

 beneath, ending in a short nipple, splitting into several stout 

 bracts Ph. conica Shimer. 



17. Flat above, either flush with, or sunken below the surface. Globular 



or pyriform beneath and more or less constricted at base ; with or 

 without a distinct nipple, which, when present, splits into several 

 bracts Ph. c. -avellana Riley 



18. Size medium ; quite flat above, usually with a more or less distinct 



median depression ; prominent and conical beneath ; not constricted 

 at base. Nipple distinct, surrounded by short bracts. 



Ph. symmetrica n. sp. 



19. Large, more or less irregular ; convex above ; more prominent and 



conical beneath, splitting at maturity into several very long bracts. 



Ph. notabilis n. sp. 



20. Large ; globular ; projecting about equally on both sides ; the nipple 



short, with four to five short, stout, pubescent bracts surrounding 

 the orifice, curving ou'wards when old Ph. c.-globosa Shimer. 



21. Large ; pedunculate and more or less elongated ; suspended from the 



under surface by a slender petiole, quite sticky when fresh ; split at 

 the apex into several long filaments Ph. c. -gummosa Riley. 



Phylloxera rimosalis Pergande, n. sp. 



PI. IV., fig. 24; PI. IX., fig. 54. 



A very large and conspicuous gall, growing always upon the 

 leaves of Hicoria tomentosa, bearing a great resemblance to the gall 

 of Ph. c.-scissa, from which it differs in the round, not elongated, 

 orifice and in some other characters. 



It is not uncommon along the Potomac near Washington and 

 affects more generally 'the terminal leaves of the more succulent 

 young shoots. It matures somewhat later than most of the 

 other galls, the first winged females occuring the latter part of 

 May. It grows generally singly, though occasionally 2-4 may 

 occur on the same leaf, in which case they tend to become more 

 or less cofiuent, so as to form a large, flat mass ; each retaining, 

 however, its cell independently. It forms upon any part of the 

 leaf, often very close to the edge, and may extend across two or 



