1 60 WHEELER. 



labrum ; st., stomodaeum ; tc, tritocerebrum ; md.g., mandibular ganglion ; en., 

 entoderm ; s.b., suboesophageal body ; coe.,^ coelom of mandibular segment. 



Fig. 62. Frontal section through the head of an embryo in Stage F (Fig. 6, 

 PI. I). X 175. pc} (p.g), optic ganglion; md., mandible. Remainmg letters as 

 in Fig. 61. 



Fig. 63. Transverse section through the suboesophageal body from an em- 

 bryo in Stage G (Fig. 7, PI. I.). X 500. 



Fig. 64. Section through suboesophageal body of larva 7 mm. long. X 500. 



Fig. 65. Section through the suboesophageal body of a nymph i cm. long, 

 X 500. 



