BIOLOGY OF SOME COMMON LAMPYRID.E. 



55 



conditions at different periods. The largest number hatched 

 on the twenty-sixth day. The newly hatched larvae are not 

 pigmented for a period of a few hours, but they soon resemble 

 the mature larva in shape and appearance, except for their mina- 

 ture size. At this stage they meas- 

 ure about 2.25 mm. in length. As 

 nearly as could be determined the 

 larvae were in the fourth instar by 

 winter. The first two molts take 

 place rather early in the life of the 

 larva, the first occurring at about 

 the age of two or three weeks. 

 The mature larva (Fig. 7) is elon- 

 gate, rather narrow, varying from 

 1619 mm. in length, and it is 

 about three times as long as it is 

 wide. The head is small, a little 

 less than one third as wide as the 

 prothorax, and it can be withdrawn 

 into a pouch within the thorax. 

 The Antennae are three-jointed, the 

 mandibles are arcuate and notched 

 near the middle. The legs are some- 

 what spinose and of nearly uniform 

 length. The body is much flat- 

 tened. The prothorax is rounded 

 on the anterior and lateral sides 

 and subtruncate behind, much the 

 same as in the adult. This is the 

 largest of the body segments. 

 From the metathoraeic segment to 

 the caudal end of the larva the ter- 

 gites are concave posteriorly espec- 

 ially the caudal ones. Each bears a spine on its caudo-lateral 

 margin. The head, mouth-parts and tergites are colored a dark 

 brown, except for a few irregular pale yellowish areas. The 

 dorsal surface is more or less irregularly coarsely punctate. The 

 last segment of the abdomen is provided with numerous retrac- 



FIG. 7. Photunis pennsylvanica 

 larva, full grown, dorsal view. 



