DIPTERA 



123 



III. With a puparium in hand, note. 



1. The cylindric, capsule-like form. It is produced by the 

 contracting and hardening of the old larval skin. 



2. The larval mouth hooks solidly, held in the hardened 

 skin at the more pointed front end. 



3. The mesothoracic spiracles similarly sealed in, a little 

 farther back. (These are hard to see.) 



4. The more evident posterior spiracles at the rear. 

 If the puparium be carefully opened, there may be found 



within a soft, white pupa, bearing the partly fashioned wings, 

 legs, antennae, etc., of the adult. 



