;{'Jll THE CANADIAN KNToMOUMJlbT. 



approached the speed of flight appears lo diminish, and as the final point 

 is reached ilie insect flies very slowly in a small rising helix, or, if flying 

 straight, may come to an almost complete stop. Occasionally the flash is 

 followed by a residual phosphorescence, similar to that observed with the 

 pyra/is, and rather more rarely the flash is not ended suddenly, but 

 allowed to fade out more gradually, in a manner resembling the normal 

 flash of the py talis. 



Anotiier natural mode of light emission of this insect consists of a 

 single, momentary bright flash, lasting only a small fraction of a second, 

 and delivered without respect to location or manner of flight ; these 

 flashes are apparently isolated instances of the flashes emitted by the 

 insect when in captivity, as will be described, or of the last natural mode 

 of light-emission which I have noticed. This last inelhod, which I have 

 observed only three limes, consists of a vertical drop or fall of several 

 feet — about ten feet in each of the three cases noted — during the whole 

 course of which the insect is flashing rapidly. On the third occasion on 

 which I noticed this failing flight, the insect continued to flit around the 

 weeds near which he had dropped, still flashing raj)idly. 



In captivity the pyralis soon loses its luminous propensity, and 

 attains a quiet, slow-creeping condition, in which it gives no light, or only 

 occasional flashes. The pennsyi'vanica, however, is very restless when in 

 captivity, running rapidly around his prison, and flashing almost continu- 

 ously at intervals of about a second, these flashes never reach the full 

 brilliancy of ihe natural coruscations of the insect, but are still quite bright. 



The males of Photinus consanguineui, P. scintillatis and Ltcontea 

 ati>^u/(Ua all emit their light in short, bright flashes, apparently without 

 relation lo ihcir manner of flight. The augu/a/a emits two such flashes, 

 separated by a fraction of a second's interval, followed by a longer interval 

 before the next two. The consanguineus usually emits a single flash, 

 much shorter and more sudden than that of the pyralis, sometimes 

 followed by a residual phosphorescence, similar to that of ihc pyralis ; 

 , occasionally, too, I have seen them give a twinkling light, suggestive of 

 \.\\Q pennsylvanica. The males of both of these species were first captured 

 under the impression that they were the pennsylvanica, only the light 

 being observed before capture. In both of these species the luminous 

 organ of the male is confined to the ventral surfaces of the two abdominal 

 segments next to the last. I have not yet captured a living female of the 

 c0fisanj;ut/uus; the female of the attgulata has an organ of irregular shape, 

 situated on the ventral surfaces of the same segments as in the male ; the 



