190 Maine Agricultural Experiment Station. 1918. 



The Prepupa. 



Formation of the prepupal cell. As is described more in 

 detail under A. corni on page 168, the prepupa constructs a 

 rude cell not far below the surface of the ground, as soon as it 

 enters the soil. 



Coloration. When the larva first enters soil as a prepupa, 

 the head, shields, and legs are shining black, the body dark 

 golden yellow, and the tubercles very dark brown. During pre- 

 pupal life the body becomes somewhat duller at first, and the 

 tubercles much lighter. In the late prepupa, the mesothorax 

 and the metathorax are golden yellow above, and the general 

 aspect of the body is golden brown above and golden yellow 

 ventrally. All of the tubercles are light brown. 



The Pupa. 



The molt to the pupa. The prepupal skin splits exactly as 

 in the case of a larval molt, beginning at the base of the mid- 

 dorsal line of the metathorax. The pupa wriggles out through 

 the opening thus formed, simply by the alternate contraction 

 and relaxation of the somatic muscles, the head and thorax com- 

 ing out first and later the abdomen. This molt requires about 

 50 minutes. The pupa is always formed with the ventral aspect 

 uppermost, and it remains in this position throughout the 

 period. 



As was pointed out in the case of the alder flea-beetle 

 (Bulletin 265, page 265), there is no homology between the 

 larval legs and the imaginal legs. At the beginning of the molt, 

 each leg, though fully formed, is curled up into a little pad at 

 the base of the larval leg, but as soon as they are free from the 

 old cuticula, they are straightened out so as lie in the position 

 normal to the pupa. The wings and elytra lie pushed ventrad 

 in the prepupa beneath the larval cuticula, in much the same 

 relationship that they have in the pupa. 



As is to be expected, the pupal setae lie flat on the body 

 wall between the larval and pupal cuticulae, and do not extend 

 up into the larval hairs. As soon as they are free from the 

 larval cuticula they spring up into the normal position. 



