518 



Fig. 16. Leg of pupa two days old (x90). The leg muscles 

 are clearly seen. 



Fig. 17. Trochanter of leg of imago (xoOO) to show the 

 nature of the muscle insertions. 



Fig. 18. Insertion of tendons of femoral muscles on tibia 

 (x500). 



Fig. 19. Tactile bristles on j&rst tarsal segment of first leg, 

 imago (xloOO). Note tlie curious modification of the somato- 

 pleural mesoderm cells to act as ueurolemmae for the nerve fibres. 



Fig. 20. Developing ovipositor from larva seven hours after 

 defaexjation ( x 150). 



Fig, 21. The same, several hours after jDupation (xl80). 



Fig. 22. Ovipositor (extruded) of imago. Note the great 

 musculature. 



Fig. 23. Section through a part of the propodeum (thirty- 

 six hour pupa) showing the powerful chitin layer (x500). 



Fig. 24. Developing pubescence on labium, fifty-six hour 

 pupa (xl500). Ohitinisation has just commenced. Note cell 

 nuclei. 



Fig. 25. Vertical longitudinal section through posterior end 

 of male, to show the migration of segments to form the penis. 

 Note cell proliferation in ninth segment (xl50). Fi'esh pupa. 



Fig. 26. Ventral view of extremity of male — two-day pupa 

 (xl50). 



Plate XVIII. 



Fig. 27. Longitudinal section of posterior end of male — 

 fifty-six hour pupa (xl80). The cuticular sheath represents the 

 position of the segments before invagination occurred. 



Fig. 28. Integument undergoing metamorphosis, ventral 

 abdominal region of larva eight hours after defaecation. Note 

 the greatly hypertrophied larval cells with large nucleoli, ^ all 

 degenerating. Only a few leucocytes are present. Note the small 

 embryonic cells growing over them (xl200). 



Fig. 29. Surface view of a proliferating imaginal disc. The 

 larval cells a,re degenerating. Some of the embryonic imaginal 

 cells are undergoing amoeboid movement (x), From the larva, 

 shortly after defaecation (xl(X)0). 



Fig. 30. Section through integument of larva eight hours 

 before pupation (xl200). Note the empty cell membranes (z) and 

 granular degeneration globules, free, or still within cells. 



Fig. 31. Integument from posterior extremity of eight-hour 

 pupa, showing accumulation of degeneration globules amongst the 

 cells of the renovated integument. A leucocyte and a degenerate 

 larval cell are also seen (xl200). 



Fig. 32. Section through mid-dorsal abdominal integument. 

 A disintegrated in tegumental cell is seen, apparently preventing 

 the closing in of the imaginal cells. The heart is also seen 

 (xl200). From the larva twelve hours after defaecation. 



Fig. 33. Integument of head showing development of scale- 

 like ''bosses." Note that a protoplasmic "mould" precedes the 

 secretion of the similarly shaped cuticle ( x 1500) — fifty-two hour 

 pupa. 



Fig. 34. Developing spine of leg (xl200) — fifty-two hour 

 pupa. 



Fig. 35. Developing abdominal bristles (xl200) — fifty-two 

 hour pupa. Note the formation of a "mould" by the integu- 

 mentai cells, previous to cuticle secretion. 



