THE PUPA, 29 



Substance. — During the first stages of the pupa, it 

 consists of a membraneous sack filled with a milky fluid, 

 in which the forming membranes of the perfect insect 

 float, and may be separated from each other by the point 

 of a pin. 



These parts, in time, fill up the larger portion of the 

 case or puparium. In some pupoe this skin is smooth, in 

 others it is covered with pimples and warts. While 

 among some of the hawk-moths, it is covered with pits or 

 depressions, or curiously shaped and even clothed with 

 hair. 



The figure and parts of incomplete pup£e, or those that 

 resemble the perfect insect, are very various and nothing 

 will be here said about them, but the complete pup?e or 

 chrysalids are more uniform in their shape and parts, 

 and the observance of them may be directed under the 

 following plan : 



Pupa of Papilio mactiaon. 



1st. The Head Case, or Cephalo-theca. 



2d. The Trunk Case, or Cyto-theca. 



3d. The Abdomen Case, or Gastro-theca. 



The Head Case is the armor or sheath of the head, and 

 several portions of it may be recognized as the antennoe, 

 case, the tongue case, and eye case, etc. 



The Trunk Case consists of two parts, the upper, or 

 dorsal, and the lower, or pectoral. The dorsal portion 

 comprises the thorax proper of the insect, and consists of 

 three parts or segments, which take the names of the 



