BIOLOGY OF SOME COMMON LAMPYRID/E. 65 



cells, when held against the light, allowed small rays to pass 

 through, giving evidence of their slight porous nature. The 

 pupal-cell, however, makes a sufficiently well-constructed cham- 

 ber to protect the pupa from drying or other injury. The 

 reason that the larva usually seeks a damp locality previous to 

 pupation is probably for the purpose of choosing a place where 

 excessive drought will not be liable to affect it during trans- 

 formation. 



By the time the pupal-cell is constructed the larva becomes 

 very sluggish, its body becomes distended and in from one to 

 three days the cuticula splits down the anterior half of the 

 back, and the pupa gradually comes forth. From this time, 



FIG. 15. Photurus pennsylvanica pupal chamber completed, internal view with 



pupa in position. 



throughout the entire pupal stage, it lies on its dorsal side within 

 its pupal-cell, and is largely supported by the long lateral setae, 

 which project from each of the thoracic and abdominal tergites 

 (Fig- 15)- 



The straightened out pupa measures about twelve mm. and 

 in the arcuate position ten mm. The body is somewhat de- 

 pressed, with the appendages and wing-pads rather long, and 

 with the lateral tergites drawn out at considerable length. At 

 the end of each of these appendages is a mass of coarse bristles. 

 The color of the pupa is yellowish white. It is quite active and 

 can move about considerably within its pupal-chamber. 



Throughout the entire pupal period the light-organs, that 

 were functional in the larva, can be distinctly seen to emit light, 



