120 



THE t A N A I » I A X J BNT< (MOLOG1 BT. 



larva continues to feed, as in the first three stages, by separating the 

 epidermis and increasing the extent of the mine. A comparison of the 

 lower figure, which represents the head of a flat larva in the fifth instar, 



m 



Ir 



m \ r 



- a 



m 





I'n.. [2.— Upper left hand: Head of cylindrical larva. I'pper right 



hand: Head in Gracilarian stage. Lower figure: Head of Hat 



larva l/rlabrum; >n mandibles; m. />. maxilla and maxillary 



palpus;/ labium ; /. /. labial palpus; u antenna; o ocelli). 



with the upper ones, the left of which represents the head of a larva of the 

 cylindrical group in the later stages, the right that of a typical Gracilarian 

 stage (third instar) of one of the cylindrical group, will show that there is 

 a greater structural difference between the fourth and fifth instars of the 

 flat larva and the true Gracilarian instar than there is between the flat 

 larva and the ordinary cylindrical larva, where the difference is more 

 quantitative than qualitative. The fact that maxillae and maxillary palpi 



