FlLtEFLIES AM) (iLoW-WVllMS AM) TEEILI LIGHT. WS 



(_)f late years much important wovk has been done b}^ Mr. A. 

 McDermott ('') upon North American sjiecies of Fireflies. These in- 

 sects, popularly known as Lightning — bugs, resemble the Fireflies of 

 Southern Europe mentioned above in that the male beetle flies about 

 flashing his light, while the femle larks in the grass below. But 

 whereas in the case for example of the European L. italica the female 

 would seem to shew her light on her own initiative to attract the 

 attention of passing males, in the American Lightning-bugs (and also 

 in the European species observed by Emery ) the female is more 

 modest, and shews her light only in reply to the " calling " flash of the 

 male. In the United States the number of species is Very considerable, 

 and in manj' cases two or more of them have been found flying to- 

 gether over the same ground, so that specific diiferences in the light 

 exhibited have been evolved to a high degree. A female of one species 

 will, as a rule, only reply to the flash of a male of her own species, and 

 a searching male will only respond to the answering flash of a female 

 of his own species. Specific diSerences are found to exist in the 

 periodicity of the flash, in its colour, its duration or in its direction, 

 some species rising and falling with a kind of dancing motion and 

 omitting the flash on the dip or on the rise, etc. Mr. McDermott's 

 investigations were assisted by an ingenious series of experiments with 

 small electric bulbs, which could be operated to simulate the flash of 

 the particular species under observation. A brief summary of some of 

 his results may serve as a guide to similar enquires in other parts of 

 the world. 



Photinas pi/ralis. The flash of the female is given 3 or 4 

 seconds after that of the male, and is of the same colour but of longer 

 duration and less intense. 



Females would answer in numbers to the flash of a match 

 swung in an arc to simulate the flash of a male, though as a rule not 

 more than one female would reply to a flashing male. 



A particular female would not reply to the flash of a male of 

 anothev s'pecies (P. coiisanr/uiioe as ) though she would to that of a 

 match. 



The male could also be deceived by a bulb placed in the grass 

 and flashed 3 or 5 seconds after his own flash. When the bulb was 

 flashed without the pause it was not so effective. 



(3) Canad. Enl. rjlU-lM2. 



