278 PROCEEDINGS OF THE ACADEMY OF [1897. 



12. Antenna? entirely black ; bod) T steel-blue with a rather dense 



cinereous pile, setaceicornis. 



Antenna? more or less yellowish, 13. 



13. Head subquadrate ; clypeus broadly subtruncate ; last five 



anteunal joints yellowish, congruus. 



Head transverse as usual, 14. 



14. Flagellum beneath and joints 7-10 entirely, yellowish ; clypeus 



broadly subtruncate. Length 8 mm., eitricornis. 



Flagellum beneath and joints 5-10 entirely yellowish ; clypeus 



subtriangular, its fore margin acute in middle ; length 12 mm., 



clypeatus. 



15. Wings fuscous, 16. 



Wings more or less yellowish, 17. 



16. Form slender; entirely deep black, including wings which have 



also a purplish reflection. Length 12 mm., . . nigerrimus. 



Form robust; velutinous with pale pile; last five antennal 



joints entirely and tbe flagellum beneath orange ; wings pale 



fuscous. Length 24 mm., orbitalis. 



17. Wings not fasciate with fuscous, at tbe most the apical margins 



or a spot in the third discoidal cell, fuscous, 18. 



Wings crossed by a broad fascia, 20. 



18. Thorax more or less clothed with golden pile, especially on 



dorsulum and scutellum ; wings pale yellow, with a fuscous 

 spot in third discoidal cell, body with a steel-blue reflection, 



hexagonus. 



Thorax not pilose ; wings not spotted, 19. 



19. Wings bright yellow, apical margin narrowly fuscous ; clypeus 



somewhat hexagonal, fore margin incurved ; serration of hind 

 tibiae indistinct ; middle segment transversely striated, . . . 



fuscomarginatus. 



Wings vitreous, having the appearance of isinglass or fish-glue ; 

 clypeus transverse, subtruncate ; serration of hind tibia? very 

 strong, •. vitreus. 



20. Middle segment densely clothed with golden pubescence trans- 



versely striated ; hind tibia? indistinctly serrated, abdomen 



subpetiolate, auratvs 



Middle segment nude, smooth ; hind tibia? coarsely serrated ; 

 abdomen subsessile, convergens. 



21. Wings black, with bluish reflection; dorsulum carinated apic- 



ally; clypeus broadly truncate mammillatus. 



