242 CHARLES R. STOCKARD. 



to its leafy food. In crawling up the young insect waves its 

 antennae to feel the way just as does the adult and reaches out 

 with the first legs to grasp the object located by the antennae. 



Finally the young like the adult is more or less nocturnal in 

 its movements. During the day they sit motionless with the 

 first legs extended forward but at night they become active and 

 move about to feed. The food of the adult is limited to the 

 leaves of Suriana. I have made no attempt to feed the young 

 since they may be kept alive for about one week after hatching 

 without taking food. 



THE THIN CURVE OF THE FEMORA WHICH FITS AGAINST 

 THE VENTRO-LATERAL SURFACES OF THE HEAD. 



When the first pair of legs are extended forward the femur of 

 each is so curved near its proximal joint as to fit perfectly against 

 the ventro-lateral parts of the head and at the same time leaves 

 the eyes uncovered, Fig. I, A and B. The curved portion of 

 the femur is also very thin in a lateral direction and thus when 

 pressed closely to the head the legs go out as almost straight 

 lines instead of bulging around the head to any great extent. It 

 seems difficult to believe that the first pair of legs could through 

 chance variations or mutations have come to fit so perfectly 

 around the sides of the head and at the same time to have their 

 dorsal line so curved as to leave the eyes uncovered. It must 

 be remembered that when the first legs are in the extended posi- 

 tion the head presses against the dorso-lateral surfaces of the 

 femur and not straight against the inner lateral surface only. 

 This arrangement may be better understood by a close examina- 

 tion of the dorsal and lateral views given in Fig. I , A and B. 



The possibility suggests itself that the perfection of the fit is 

 attained during the life of the individual since the legs are so 

 habitually pressed against the head for about twelve hours daily. 

 To test this it became desirable to study newly hatched indi- 

 viduals in order to find whether the femur curve was as perfectly 

 adjusted in them as in the adult. A careful examination of about 

 one hundred Aplopi shortly after emerging from the egg has con- 

 vinced me that the curve of the femur is as true to the head pat- 

 tern in the newly hatched young as in the mature insect when 

 several months old. 



