BIOLOGY OF SOME COMMON LAMPYRID^. 71 



digestive juice is constantly being exuded through the mouth 

 as well as by these canals, while the larva is feeding, which serves 

 to break down and partially digest the tissues of the host. Fur- 

 ther, it was evident that small portions of undigested flesh, as 

 well as food that was nearly digested, was taken into the mouth, 

 where it was bathed in the digestive juices and worked back 

 and forth by means of the two mandibular teeth, and that liquid 

 food together with very small portions of partially digested food 

 passed into the crop and intestinal region where digestion was 

 completed. As far as could be determined, the mandibular 

 canals did not serve for the intake of foods, as in the Chrysopidae, 

 but they appeared to function, as far as digestion is concerned, 

 simply as canals for exuding digestive fluids into the host. 



At frequent intervals while feeding, certain of the larvae were 

 observed to extend the caudal filaments, twist the body around, 

 and apply them to the portion of food that was being eaten. 

 It appeared as if the larva was placing some glandular secretion 

 upon the food, or possibly helping to push it into its mouth. 



Other experiments were performed to determine whether or 

 not these larvae limited their food to snails and earthworms. 

 On successive days cutworm larvae (Peridroma margaritosa 

 Haworth, Paragrotis tessellata Harris), potato-bettle larvae 

 (Leptinotarsa decemlineata Say), squash-bug nymphs (Anasa 

 tristis DeGeer) and wireworms (Agriotes mancus Say) were 

 placed in the pots with these firefly larvae. They readily ate all 

 of the cutworm larvae, but in no instance were any of the other 

 insects eaten. 



From the above experiments it seems evident that these 

 firefly larvae feed chiefly on snails, cutworms and small earth- 

 worms. The other insects that were offered them as food were 

 chosen because they are sometimes found on, or near the ground, 

 and it was desired to see how wide a range of food they would eat. 



Although the adults have no light-organs, the larvae have 

 well developed light-organs which resemble very closely, in 

 appearance, those of the other species studied. It, however, 

 appears to be somewhat smaller and emits a less distinct light. 



Larvae were not reared from the egg to the adult, so the length 

 of their life-cycle cannot be given with certainty. Yet, since half- 



