194 AMERICAN HYMENOPTERA, 



PLATE VI. 

 Fig. 21. — Boynbus perplexus, antenna of male. xl3. 



" 22. — Bombus (Bombias) fraternus, inner spatha of male. xl3. 

 " 23.— Bombus ternarius Say. Lateral aspect of antenna of male. 



xl3. 

 " 24. — Psithyrus interruptus, spiracle bearing plate of abdomen. 



xl3. 

 " IS.— Bombus appositus Cresson. Flagellum of antenna of male. 



xl3. 

 " 26. — Bombus pennsylvanicus, tarsal claws of queen. x25. 

 " 27. — ^o;«(^«5 rt^«2.5, antenna of worker. xl3. 

 " 2S.— Bombus ternarius, inner (dorsal) aspect of apical ventral 



abdominal segment of worker. xl3. 

 " 29. — Bombus pennsylvanicus, hair from thorax of queen. x60. 

 " 30. — Bombus {Bombias) nevadensis, inner aspect of left mandible 



of worker. xl3. 

 " 31. — Bombus {Bombias) morrisojii Cresson. Ventral aspect of 



outer spatha of male. xl3. 

 " 32. — Bombus sonorus Say. Dorsal aspect of inner and outer 



spathas together. xl3. 



PLATE VIL 

 Fig. 33. —Bombus affinis, view of inner side of left mandible of male. 



xl7. 

 " 34. — Bombus affi)tis, view of inner side of right mandible of queen. 



xl7. 

 " 35. — Bombus {Bombias) morrisoni, outline of inner aspect of right 



mandible of male. x20. 

 " 36_ — Bombus bimaculatus Cre&son. Outline of inner aspect of right 



mandible of worker. xl7. 

 " 31 .—Bombus affinis, outline of inner aspect of left mandible of 



worker. xl7. 

 " 3^.— Bombus {Bombias) fraternus, outline of inner aspect of left 



mandible of male. xl3. 

 " 39. — Botnbus affinis, outline of inner aspect of right mandible of 



worker. xl7. 

 " 40. — Bombus affitiis, outline of inner aspect of right mandible of 



worker. xl7. 

 " il.— Bombus affinis, outline of inner aspect of left mandible of 



worker. xl7. 

 " 42. — Bombus ternarius Say. Outline of inner aspect of left man- 

 dible of queen. xl7. 

 " ^3.— Psithyrus interruptus^ inner (dorsal) aspect of apical ventral 



abdominal segment of female. x9. 

 " 44. — Bombus vagans, outline of inner aspect of right mandible of 



queen. xl7. 



