76 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxx. 



VIII and IX) shows the same process; the migration of pigmenc ceUs 

 from the borders of the upper series of larval areas, destrojang them as 

 such, and merging them into the now lightly pigmented dorso-lateral 

 areas. The pigment on the head shows a tendency to concentrate, 

 making this part of the dorsal surface lighter. At this stage the 

 ground color is clear yellow. The second and third series of hirval 

 areas, and the pigment spots of the legs and tail, maintain their pre- 

 vious arrangement. 



When th(> Uirva is -iS nmi. in length (Fig. 4:, Plates VIII and IX), the 

 lightness of the dorsal area is emphasized, most of the primar}- pig- 

 ment reticuhun having aggregated into the now distinct spots. The 

 spots on top of the head are further intensitied, reaching a stage of 

 development in which they remain until or after transformation. 

 The pigment-cells move awa}* from areas on both the lower and upper 

 parts of the tail at the base of the keel, marking the proportion of 

 this that will be absorbed and forming for the tail dorso-hiteral areas 

 similar to those shown in the last stage on the dorsul surface of the 

 bod}' proper. 



The pigment blotches on the legs and on the side of tail, head, and 

 bod}^ are more widel}^ separated, but the lower two rows of larval 

 areas remain intact. The ground color is possibl}' a shade more yel- 

 lowish at this stage. 



The principal change in the next stage (51.7 mm., tig. 5, Plates 

 VIII and IX) is the further development of the dorsal spots. They are 

 proljabl}' as conspicuous in the specimens tigured as the}' ever are 

 before transformation. From the same tigures it will be seen that all 

 the other features are about the same as in the preceding stage and 

 that the pattern of the legs ;ind the second and third series of larval 

 areas are in practically the same condition as in the 17.5 umi. larva. 



However the ventral tin of the tail has l)een absorbed and nearly all 

 of the pigment-cells have migrated from the dorsal keel and are col- 

 lected with the rest in a dense reticulation over the surface of what 

 will be the adult tail. The cells remaining in the keel later form the 

 few spots that exist on the mid-dorsal line of the tail in the adult. In 

 all larvaj 50 nun. or more in length the ground color has deepened 

 and is noticeably yellow. 



The changes in form of the bod}- at transformation are nuich 

 greater than those in its color, but the latter are important. In a 

 specimen 55 mm. long representing the most recently transformed 

 stage we have (Fig. 0, Plates VIII and IX) the groundcolor can scarcely 

 have changed from that of the last stage, but the dorsal spots of both 

 body and tail have attained the perfect size and detinition. The color 

 pattern of the head and legs remains about as in the last stage. Both 

 the second and third series of pigmentless areas are breaking up, how- 

 ever, anastomosing with each other and with the adjoining lighter 



