Bui. 597, U. S. Dept. of Agriculture. 



Plate 



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Stages of the Bot Flies, Gastrophilus. 



Upper left.— Gastrophilus hacmorrhoidalis: Female, side view. Upper right.— G. haemorrhoidalis. 

 Larvae attached to margin of anus of horse. Left of center.— G. hacmorrhoidalis: Last-stage 

 larva. Center. — G. intestinalis: Last-stage larva. Right of center.— G. nasalis: Last-stage 

 larva. Lower left.— G. intestinalis: Puparium, showing cap split off by fly in emergence. Lower 

 right.— G. haemorrhoidalis: Male, side view. (Original.) 



