BIOLOGY OF SOME COMMON LAMPYRID.^. 69 



in color, while the pleural regions are distinctly pinkish. On the 

 ventro-lateral sternite of the eighth abdominal segment are 

 two luminous areas, the larval light-organs. 



Similar to the adults of this species the larvae are active during 

 the day, though as a rule they are more active at night, when 

 they can be found wandering about on the ground at the edge of 

 streams apparently in search of food. Frequently, however, 

 while searching for them during the day they were found con- 

 cealed under stones and in the ground to a depth of from one to 

 two inches. On several occasions numbers of them were found 

 assembled together, where they were feeding on a captured 

 snail or earthworm. They were found most abundant at Ithaca, 

 N. Y., on the gravel at the edge of Cascadilla Creek a short dis- 

 tance below the new fish hatchery. 



Since these larvae were active during the day-time, and as 

 they readily took food, it seemed advisable to study more in 

 detail their food habits. 



Newport (1857), Meinert (1886), Fabre (1913), Haddon 

 (1915) and Vogel (1915) each studied the food habits of Lampyris 

 nocliluca. Newport evidently did not observe closely the man- 

 dibles, for he did not mention their hollow nature, which was 

 observed by the other four workers. Newport maintained that 

 the bite of the larva definitely injured the snail upon which it 

 was feeding, while Fabre took a different view, maintaining that 

 the larva injected a substance into its host in the nature of an 

 anaesthetic which paralyzed it, thus making it possible for the 

 larva to feed without being disturbed by the efforts of the snail 

 in trying to escape. 



So far as my observations go, I am inclined to believe that the 

 larva does inject a definite substance which serves to paralyze 

 and finally to kill its host. On one occasion a rather small 

 earthworm, about three inches long, was placed with six larvae. 

 In about two minutes one of the larvae, as it moved about, 

 feeling its way with its maxillary palpi and antennae, came in 

 contact with the worm. It touched it several times with these 

 structures, which undoubtedly were supplied with sense organs, 

 and then pierced the worm with its mandibles. The earthworm 

 quickly moved and was evidently slightly injured, but it soon 



