Thompson.— Anatomy of Mosquito. 
PLATE 17. 
Fig. 51. Ileum of pupa twelve hours old, showing the columnar character of 
the degenerating cells and some reconstructed epithelium {reg). cir 
m — circularis muscles. 
Fig. 52. Colon and rectum in a pupa five hours old ; temporary degenera¬ 
tion of the epithelium of the rectum. Owing to the collapsed walls 
many cells are cut tangentially and apparently lie in the lumen. 
Fig. 53. Same region in a pupa twenty-one hours old, showing the beginnings 
of a rectal papilla ( p) and the new-formed ileo-colon ( ilc ). Outside of 
this lie the remnants of the larval colon ( co ). A few of its muscles (m) 
are still recognizable. 
Fig. 54. Diagrammatic longitudinal section of a pupa five hours old. 
Fig. 55. Diagrammatic section of a pupa twenty-two hours old. The antlia 
is not yet formed. / res = ventral esophageal pouch. 
Fig. 56. Outline of section of head of pupa four hours old. * = pharyngeo- 
buccal boundary. 
Fig. 57. Outline of section of head of pupa seventeen hours old, epipharynx 
degenerated, muscles altering. * — pharyngeo-buccal boundary. 
Fig. 58. Outline of section of head of pupa twenty-five hours old, the imag- 
inal muscles and pump perfected. * = pharyngeo-buccal boundary, 
val m = el d p, ctsc ph — retr ph of figures 56, 57. epi = epipharyngeal 
muscles. 
Fig. 59. Invasion of larval colon by cells of the ileum; longitudinal section of 
pupa seventeen hours old. 
