30 gexi:i:a of hymexoptera. 



A suture betwciMi nicsntlKirax and sciiti'lliini. tlic latter with a distinct, more 

 or less elevated carinatc anterior niarjiin 13. 



i:{. — Abdomen, especially frmii lliini tn last segments, entirely or at least on lower 

 two-tliirds, covered with a rich silky ])uhescence, also head, thorax and 

 lefjs; head much widened behinil the eyes: inesotlioracic ridges parallel 



or nearly so; aganious form 14. 



Abdomen without silky ]Mibescence, almost or entirely without hairs 15. 



14. -Claws of j)osterior tarsi entire; antennic long and slender, last joint some- 

 what thicker than second, distinctly thicker than long; i>ara]«idal 

 grooves not impressed anteriorly ; scutellum as long as wide, its base 

 with an entire transverse furrow formed by a fine carina and oi)en at 



each end ; fin galls of Qiiercus cerris) 19. '■■Aphelonyx Mayr. 



Claws of po.sterior tarsi bidentate; antennse thicker and shorter, second 

 joint as long or longer than thick ; jjarapsidal grooves entire; scutellum 

 somewhat broaih-rthan long, the base with two transverse furrows, each 

 closed e.Kternally liy a carina; (in Oak-galls) IS. Cynips Linn. 



!.">. — CJiceks with a sharp furrow; antenna- distinctly 14-jointt'd. Hagellum mod- 

 erately slender, more so at tip than at middle, the joints at least IH as 

 long as thick; parapsidal grooves sharp and entire: ine.-^othorax pul- 

 i.shed ; the two de])ressions at base of scutellum sejjarated from each 

 other by a sharp carina ; metathorax above with two j)arallel ridges, the 

 disc strongly arcuate ; second joint of posterior tarsi as long as apical 

 joint, claws indistinctly bidentate; head and thorax black, abdomen 

 yellowish red; sexual form; (in Oak-galls). ..21. Trig-onaspis JIartig. 

 Othei'wise formed ; apical third of antenna} not thinner than at the middle, 

 (except in one species of Tlmaspis) Ki. 



l(i. — Entire body nearly everywhere {wlished and very shining, of a reddish 

 yellow color; cheeks shorter than lialf of the eyes; antenna; with 1.'} 

 free joints, those of apical half distinctly thicker than joints 3-."); i)ar 

 apsidal grooves sharp and entire; ba.se of scutellum with a transverse 

 groove, which is divided in two by a shar]> median carina, disc of scu- 

 tellum laterally and behind with a very di-itinct marginal ridge; meta- 

 thorax with two angularly curved ridges, divergent medially ; alxlomen 

 strongly compressed, lenticular, acute above and lu'low : marginal cell 

 hmg and open at the margin of the wing; <daws of jwsterior tarsi entire ; 



(in leaf-galls of Qiterciis cerris) •i'.i. 'Chllaspis M;iyr. 



Body not at all yellow. i)olished, also .scutellum, the disc of which is mar- 

 gined 17. 



17. — Face, occiimt. mesothorax anil mesoj)leura' polished, not hairy, black ; an- 

 tcnuic with 13-14 distinct joints; i)rothorax with two foveje near the 

 middle, immediately behind anterior margin; base of scutellum with 

 two W(dl-defined fovefc ; metathorax with two paralhd ridges; .second 

 and third .segments of abdomen united, with or without t'urrow; claws 

 of jio.sterior tarsi entire; (in Potentilla-galls)..s. Xestophanes Forst. 

 Otherwise formed 18. 



IM. — .\bdomen with second and thir<l segments unile<l, without or rarely with a 

 trace of a separating suture, .so that only six free segments appeal', seg- 

 ments 2-3 forming almost the entire abdomen ; cheeks without fuiTow : 

 the front laterally strijted ; head not wider behind the eyes; protlnuax 

 not narrowed medially; basi' of scutellum with two sharply marked 



