652 



C. B. HARDENBERG. 



The number of liooklets of the prolegs varies. The ar- 

 rangement on three examples, selected at random, was as 

 follows : 



It appears that the males do not pass throvigh the instar 

 corresponding to this fifth instar of the female. Measure- 

 ments taken of male caterpillars (which remain much smaller 

 than the female) gave a width of the head-case of 3 nun. 

 only, corresponding to that of the fourth instar of the female, 

 and during this fourth instar all caterpillai-s collected are 

 about of equal size. After the females have moulted they 

 continue growing and feeding, and during this time we find 

 the caterpillars approximately in two sizes, those that will 

 develop into females being the larger. 



The omission of this instar on the part of the males becomes 

 still more probable in view of the fact that the males pupate 

 fully a month before the females. 



Sixth Instar (Ultimate or Pkepupal Instar). 



Length of female from 24 to 34 mm., average 28 mm., that 

 of the males 22 mm. Ground colour of body on ventral 

 aspect light ochraceous salmon (XV), dorsal aspect orange cin- 

 namon (XXIX). Thoracic and abdominal legs, setiferous plates, 

 ground colour of head and thoracic shields light buff (XV), 



