ON THE DEVELOPMENT OF DERMATOBIA HOMINIS. 513 



Fig. 16. Hooks from the median ventral area of the seventh somite in surface view, showing the number and rela- 

 tive size in the two sets, one on the outer and the other on the inner skin. X64. 



Fig. 17. Hooks from the left anterior region of the fourtli somite in surface view, showing the number and relative 

 size in the two sets, one on the outer and the other on the inner skin. X64. 



Fig. 18. Isolated hook from the outer skin of the seventh somite in profile view. X64. 



Fig. 19. Stigmal fields in the last somite viewed en face as a transparent object. The small stigmata belong to 

 the outer skin and the larger ones to the inner skin. X95. 



