BIOLOGY OF SOME COMMON LAMPYRIDJE. 57 



Larvae taken into the laboratory were placed under as normal 

 conditions as possible, where various experiments were per- 

 formed to determine the possible nature of their food. In no 

 case were newly hatched larvae found in the act of killing their 

 prey, though they were observed feeding on bits of snail that 

 was cut up and placed near them. They fed much the same as 

 the older larvae, and, in fact, there can be little doubt but that 

 their food habits are similar. As the larvae were not active 

 during the daytime, and as they were disturbed by artificial 

 light, my observations on the feeding habits were largely limited 

 to the larvae of Pryopyga fenestralis which is active during the day. 

 On six different occasions a slug (Agriolimax campestris Binney) 

 was placed with six larvae of Photurus pennsylvanica and in 

 every case it had been eaten before morning. A slug (Agriolimax 

 agrestris L.) and a snail (Succinea avery Say) were put in with 

 six larvae. The snail was eaten during the first night, but the 

 slug was not killed and eaten until the third night. On two 

 occasions a small earthworm (Lumbricus terrestris L.) was placed 

 in a jar, without earth, which contained eight larvae. One was 

 killed and eaten the second night, and the other on the fifth 

 night. On two occasions a very large specimen of Limbricus 

 lerrestris was placed with twelve larvae. In each case the earth- 

 worm was not disturbed, though it remained with the firefly 

 larvae for over a week, and they received no other food during 

 that time. On two occasions a potato-beetle larva (Leptinotarsa 

 decemlineata Say) was placed in a jar with six larvae and each 

 time it was eaten the first night. On two occasions cutworm 

 larvae (Paragrotis messoria Harris, Paragrotis tessellata Harris 

 and Peridroma margaritosa Haworth) were each placed in jars 

 with six larvae and in every instance they were eaten the first 

 night. Finally, on four different nights, two second and two 

 third stage squash-bug nymphs (Anasa tristis DeGeer) were 

 placed with six larvae, and in each instance they were eaten 

 before morning. Sowbugs (Oniscus asellus Paulmeier), wire- 

 worm larvae (Agriotes mancus Say), ants (Formica sp.) and coleop- 

 terous beetles including the common ground beetles (Nebia 

 pallipes Say and Chcelnius pennsylvanicus Say) were placed in 

 with these larvae, but they were never eaten, indicating that the 



