52 WALTER N. HESS. 



sanguineus). In each case, however, the firefly being devoured 

 was a male, which had probably attracted the Photurus by means 

 of its frequent flashing, as the females of these species flash very 

 rarely, except in response to the flash of the male. In captivity 

 the female was often found devouring the males of her own species, 

 and occasionally a member of her own sex. The males were not 

 found feeding, though it seems probable that they also are 

 predatory at times. 



Though both sexes fly readily, comparatively few females were 

 found on the wing during the early part of the season, although 

 later (about July first to fifteenth), when it seemed evident that 

 there was a less abundance of males, the females were found 

 flying fully as much as those of the opposite sex. The flight 

 began about 8:15 P.M. and continued until after 10:00 P.M., 

 although by that time comparatively few were flying. Some 

 have been observed on the wing as late as I :oo A.M. Unlike 

 our other native species, these fireflies frequently fly high and 

 their flashes can often be seen in the tops of the highest trees. 



The flashing of this firefly is very distinctly different from that 

 of any of our other native species. Like the other fireflies, these 

 have definite periods of flashing. The male flashes three, four, 

 and even five times in rapid succession at each period. The 

 flashes are bright, although they become less distinct at the 

 end of each period. In the case of the female the number of 

 flashes at each period is reduced to three, two or one. There 

 is usually a longer period between the flashes than in the male 

 and they are less distinct. These periods of flashing occur at 

 rather regular intervals of about eight to ten seconds. The 

 male flashes slightly more frequently than the female. When 

 on the ground the brilliancy and regularity of flashing, on the 

 part of both sexes, seems to be the same as when they are flying. 



It is agreed by most students of fireflies that the light-emissions 

 serve to bring the two sexes together, although McDermott 

 (1911) and Williams (1917) seem to doubt that they can serve 

 such a function in this species. In the other native luminous 

 species that were studied there is a definite interchange of flashes, 

 in which the female responds to the flash of the male. In 

 Photurus the female is an active flier and flashes frequently, 



