8 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. 60. 



2. Pupariiim very small ; spiracular protuberance entirely smooth and 



shining 3 



Puparium of medium size or larger ; protuberance only partly smooth 4 



3. Posterior spiracular protuberance, cone-shaped, with a groove between the 



stigmal plates (No. 45) Alophora pulverea Coquillett. 



Posterior spiracular protuberance deeply bifid on apical half and pointing 

 obliquely downward (No. 46) Phorantha occidentis Walker. 



4. Protuberance granular at base only 5 



Protuberance entirely granular or spiny 



5. Spiracles widely separated, granular on the basal half only. 



(No. 47) Frontina ancilla Walker. 

 Spiracles solid and granular at the base, deeply bifid on apical half. 



(No. 48) Clytiomyia flava Townsend 



6. Spiracles quite spiny on the sides, subdorsal ; anterior spiracles prominent. 



(No. 49) Plagia americana Van der Wulp. 



Spiracles vex'y rugose on the sides ; slits with short branches ; spiracles at 



the apex (No. 50) Acemyia dentata Coquillett. 



7. Spiracles subdorsal; three lobes somewhat claw-shaped. 



(No. 51) Eutrixa exile Coquillett. 

 Spiracles near the apex of puparium 8 



8. With four slits ; stigmal plates very small. 



(No. 52) Phorocera erecta Coquillett. 

 With three or six slits in each plate 9 



9. With six slits in each plate 10 



With three slits in each plate 12 



10. Puparium cylindrical, slightly concave on the dorsum ; slits nearly straight. 



(No. 53) Cryptomeigenia theutis Walker. 

 Puparium greatly enlarged on the posterior end 11 



11. Stigmal plates contiguous ; slits angulated. 



(No. 54) Biomyia lachnostemae Townsend. 

 Stigmal plates small, widely separated ; slits simple, only faintly curved. 



(No. 55) Cryptomeigenia aurifaeies Walton 



12. Segmentation distinct on the dorsocaudal end, concave on dorsocephalic 



half ; stigmal plate triangular, with three very small slits. 



(No. 56) Hyalomyodes triangulifera Loew. 

 Segmentation indistinct 13 



13. Button on stigmal plate very large, protruding 14 



Button on stigmal plate normal 16 



(4. Button quadrate (No. 57) Admontia hylotomae Coquillett. 



Button rounded 15 



15. Two upper slits nearly parallel ; posterior end of puparium tapering. 



(No. 58) Masicera, species (near exilis.) 

 Two upper slits divergent ; posterior end not tapering. 



(No. 59) Frontina armigera Coquillett. 



16. Posterior end of puparium very rugose ; slits wide, nearly parallel. 



(No. 60) Amobia confundens Townsend. 

 Posterior end not rugose 17 



17. Stigmal plates flush with surface ; located in a triangular area. 



(No. 61) Exorista amplexa Coquillett. 



Stigmal plates above the surface of the puparium ; puparium large 18 



IS. Puparium with a constriction near the posterior end forming a segment- 19 

 Puparium without a constriction 20 



