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small, spiraeular cavity, easily closed and having a smooth 

 rim : it contracts to a pupa, which is quite uniformly 

 rounded at each end. The Sarcophaga larva is more 

 truncate behind, with fleshy warts on the rim of the spirac- 

 ular cavity, and with a more tapering head : it contracts 

 to a pupa, which is also truncate behind, and more taper- 

 ing imfront, where the prothoracic spiracles show as they 

 never do in Tachina. 



