PLATE 1 



EXPLANATION OF FIGURES 



3 Cross-section of the urinary bladder of a larva in the fifth stage. X 400. 



4 Cross-section of the coelomic portion of a larva in the fifth stage. X 220. 



5 Longitudinal section of the common stem (cs.) and the urinary bladder 

 (ub.), showing the multiplication of the imaginal cells, cp., coelomic portion. 

 X 90. 



6 A portion of the rectum from a cross-section of a larva which has just begun 

 to spin the cocoon, showing the included portion of the malpighian tubes, p., 

 peritoneum. X 90. 



7 A portion of the rectum from a cross-section of a larva on the day before 

 pupation, showing the disintegration of the included portion of the tube. X 400. 



8 Cross-section of the coelomic portion of a pupa two days old, showing the 

 separation of the basement membrane from the epithelial cells. X 400. 



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