Plate VIII. 



Figs. 25 and 2G. Showing the complete coalescence of the parts of the 

 rostrum to form the flat rostral plate, ros., the formation of a mandibular 

 segment on the base of the pedipalp, md. pdp., the partial separation of 

 the neuroblasts in the cerebral and optic lobes as indicated by then' frac- 

 tured appearance, the deepening of the anterior and lateral grooves, and 

 a considerable increase in the growth of the optic fold, o. f. 



The condition shown in Fig. 25 is somewhat abnormal and is not so far 

 advanced as that shown in Fig. 2G. 



