250 HYMEXOPTERA OF AMERICA. [PART I. 



5. Insect black aud dull rufous, with yellowish ornaments ; 



body velutiuous, hairy. 



6. Second abd. segment not canaliculate. 108. Guerreri. 



G, G. Second abd. segment having its margin strongly canali- 

 culate. HI- Morelii. 

 5, 5. Insect ferruginous aud black, with bright yellow ornaments', 



,. . . , .. 94. ( annulatus. 



abdomen polished, not velutmus. •> 



10b". t pratensis. 



4,4. Metathorax forming on each side a dentiform angle. 



.". .^ize very large. 



G. Wings smoky. 84. dorsalis. 



„ „ „ r . - 85. f proctus. 



6, G. Wings ferruginous. < l 



oo, l consors. 



5, 5. Size medium or small. 



G. Superior angles of piothorax not prominent. 



99. i apicalis. 



7. Wings smoky. 94. < annulatus. 



92. *■ arvensis. 



7, 7. Wings ferruginous. 



8. Second abd. segment not canaliculate. 



9. Size smaller. 98. spectabilis. 



n . _. , 94. f annulatus. 



9,9. Size larger. < 



99. t apicalis. 



8, 8. Second segment more or less canaliculate. 



9. Post-scutel crenulate ; abdomen conical. 



89. Iturbidi. 



9, 9. Post-scutel not crenulate ; abd. not conical. 



111. Morelii. 

 6, 6. Superior angles of metathorax prominent, separated from 

 post-scutel by a fissure or a notch. Size medium. 



7. Margins of segments 2d, 3d, reflexed ; post-scutel -ellow. 

 8. All the segments margined with yellow. 



82. H'uhilgi, var. 



8, 8. Segments 1-3 margined with yellow. 



82. IJidalgi, var. 



7,7. Margins of segments 2, 3 depressed, but not reflexed; 

 post-scutel black. 83. Boscii. 



3, 3. Body black, adorned with yellow or luteous. 



4. Ornaments luteous. 



5. All the abd. segments margined with luteous. 



103. leucomelas. 

 5,5. Only 2d segment margined with luteous. 101. Megcera. 

 4, 4. Ornaments yellow. 



5. Post-scutel black. 



6. Segments 1, 2 margined with yellow; wings cloudy, 

 brownish. 83. Boscii. 



6, 6. Segments all margined with yellow; wings ferruginous. 



91. Alvaradi. 



5, 5. Post-scutel adorned with yellow. 



