34 OENERA OF HYMENOPTERA. 



thorax very coarsely transversely wrinkled ; parapsidal grooves in front 

 wanting; (in galls of Qiiercua cerris) 14. *Synophru8 Hartig. 



Second abdominal segment not overhanging all the others; face with radi- 

 ating striie; niesothorax transversely wrinkled anteriorly; clypeus, at 



Usist laterally, well devel()j)ed 8. 



S.—X suture between niesothorax and sciitellum ; anterior margin of scutellum. 

 in front of the transverse groove, not thickened and carinate, or very 

 rarely feebly so: posterior margin of niesothorax iiiediaily arcuately 

 emargiuate, and laterally more or less arcuately prolonged or rounded 

 out. each pronounced eniargination has also an interrupted transverse 

 furrow, arcuately curved ; parapsidal grooves wanting or not distinctly 

 marked; abdomen pe^tiolate ; (in Oak-galls). ..2t). Neuroterus Hartig. 



A more or less distinct ridge on middle of anterior margin of .scutellum.. 9. 

 9.— Cheeks with a sharp furrow ; antenna'! distinctly 15-jointed, tiagelluni rather 

 slender, all the joints at least three times as long as thick ; me.sothorax 

 polished, with sharply defined, entire parajisidal grooves ; the two foveje 

 at base of scutellum separated by a carina; metatiior.ix with two .supe- 

 rior parallel ridges, which at the middle of the disc are strongly diver- 

 gent,. then angularly bent and converging to the thoracic peduncular 

 articulation; (in Oak-galls) 21. ^Trigronaspis Hartig. 



Otherwise formed 10. 



10. — Antennae with 14 free joints; mesothorax finely wrinkled, punctured and 

 hairy (in P. »!ilvestns O. S. finely alutaceous and shining) ; base of scu- 

 tellum with two sharply marked fovew ; metathorax with two parallel 

 ridges; abdomen sessile, segments 2-3 connate, with a more or less dis- 

 tinct suture ; marginal cell entirely closed ; claws of posterior tarei bi- 

 dentate ; (In<iuiliiie in Rose and Rubus galls) 9. Periclistus Fiii-st. 



Otherwise formed 11. 



11. — Face, occiput, niesothorax and me.sopleui-se polished, naked and black ; cheeks 

 about half .as long as the eyes ; antenna' 14-jointed ; prothoi-ax, near 

 middle of anterior margin, with two fovete, the space between these 

 fovese polished and bare; base of .scutellum with two sharply defined 

 furrows; metathorax with two parallel, longitudinal ridges; marginal 

 cell not very elongate; claws of po.sterior tarsi entire; (in PuteiiHlla 

 galls) 8. *Xestophanes Forst. 



Otherwise formed 12. 



12.— Cheeks half as long as the eyes; base of scutellum with two sharply marked 

 fovese (except in Timaspis) ; abdomen .sessile 13. 



Cheeks less than half as long as the eyes ; marginal cell open and unusually 



elongate 1(5. 



13.— Claws of posterior tarsi distinctly or indistinctly bidentate. in the latter 

 case the niesothorax sharply, transversely wrinkled and the marginal 

 cell entirely closed and short; antennai with 14 free joints 14. 



Claws of posterior tarsi entire 15. 



14. — Mesothorax jMdished or nearly so, with sharply defined parapsidal grooves ; 

 fovese at base of scutellum deep or moderately deep and not transverse ; 

 marginal cell open at wing-margin, sometimes closed in D. radieum : 

 claws of posterior tarsi bidentate ; (in galls of Rubun and PotentiUa). 



15. Diastrophus Hartig. 



