AKT. 29 IMMATURE STAGES OF SAE.COPHAGID FLIES GREENE 5 



21. Spiracular plates with a narrow ridge on tlie lower inner edge ; slits long, 



narrow ; the inner slit with a bend just above the middle. 



No. 19, Sarcophaga haemorrhoidalis Fallen. 



Spiracular plate with a narrow ridge between the two inner slits; slits of 



nearly equal length, broad- No. 20, Chaetoravinia quadrisetosa Coquillett. 



22. Anal opening located on a definite tubercle; .spiracular slits short, slightly 



curved ; plate with an extended edge along the upper and outer edges. 



No. 21, Sarcophaga rudis Aldrich. 



Anal opening not as above 23 



2o. Spiracular plates rounded, lobes flattened with three straight slits of 



equal length No. 22, Sarcophaga pachyprocta Parker. 



Spiracular plates not flattened , 24 



24. Spiracular plate with the first slit bent sharply downward to the right- 25 

 Spiracular plate not as above 26 



25. Spiracular plate with the middle slit quite long ; posterior cavity large. 



No. 23, Sarcophaga barbata Thomson. 

 Spiracular plate with the middle slit short, posterior cavity small. 



No. 24. Sarcophaga bisetosa Parker. 



26. Posterior cavity round or nearly so 27 



Posterior cavity elliptical 28 



27. Spiracular plate with an oblique point on the first lobe. 



No. 25, Sarcophaga plinthopyga Wiedemann. 



Spiracular plate without the above point; spiracular plate more quadrate; 



lobes broad No. 26. Helicobia helicis Townsend. 



28. Spiracular plate with the first slit much longer than the second or third. 



No. 27, Sarcophaga uliginosa Kramer. 

 Spiracular plate not as above 29 



29. Lobes of plate broad ; slits short and broad ; posterior cavity on but below 



the horizontal axis ; lower edge of cavity with short rugosities. 



No. 28, Sarcophaga davidsoni Coquillett. 

 Lobes not as above 30 



30. Spiracular slits short 31 



Spiracular slits long 32 



31. Spiracular plate rounded; slits slightly bent; posterior cavity not elliptical; 



no indication of segmentation on the posterior end of pupa. 



No. 29, Sarcophaga prohibita Aldrich. 

 Spiracular plate more rectangular ; first slit slightly curved, with the other 

 two slits parallel ; posterior cavity elliptical ; one segmental line promi- 

 nent on the posterior end of the puparium. 



No. 30, Sarcophaga morosa Aldrich. 



32. P'irst two slits longer than the third 33 



All slits of about equal length 34 



33. All three slits slightly arcuate ; a conical tubercle on each side of anal 



opening No. 31, Sarcophaga latisterna Parker. 



First two .slits slightly arcuate ; third slit quite short and straight. 



No. 32, Sarcophaga marginata Aldrich. 



34. Puparium with indications of segmentation on the posterior end; first slit 



slightly sinuous ; a tubercle on each side of the anal opening. 



No. 33. Sarcophaga bullata Parker. 

 Puparium smooth 35 



