258 S. O. MAST 



At that time the insects were very abundant. Dozens of them 

 could be seen at a time flying about over the lawn and garden 

 every evening. I do not know how early in the spring flight 

 begins but after the first of August there were onlv very few 

 seen, usually not more than two or three each evening. In 

 October some were still seen. They probably continue to appear 

 until prevented by frost. 



The two sexes in the species studied are nearly alike. There 

 is ordinarily but little difference in size, and the wings of the 

 female, contrary to what is found in many species, are apparently 

 as fully developed as are those of the male. The eyes, however, 

 are much larger in the male than in the female and the luminous 

 area is also much larger. In the male it covers the entire ventral 

 surface of the three posterior segments, in the female only a 

 portion of the ventral surface of the third. Thus, while the 

 two sexes are similar in general appearances, they can readily 

 be distinguished from each other. 



HABITS 



During the day time these fire-flies are found in dark crevices 

 or under ground. In the evening when it is still light enough to 

 read readily they come out. The males soon take wing and fly 

 about, glowing fairly regularly at intervals of about five seconds. 

 Owing to lack of proper instruments I was unable to ascertain 

 the intervals very accurately. However, I found none less than 

 four or more than six seconds. The females climb to the tips 

 of blades of grass or onto other objects and usually remain 

 quiet; they do not fly. Among all of the specimens captured 

 on the wing during the entire season not a single female was 

 found. My notes contain a record of sixty-one specimens taken 



that the small ones were dwarfs and that all are of the same species and identical 

 with the fire-flies most common in Washington. If this identification is correct 

 my studies were made on the same species as were those of Osten-Sacken and the 

 major portion of those of McDermott. The reactions of the specimens found at 

 Smithsburg, however, differ in at least two important respects from those of the 

 specimens found at Washington judging from McDermott's description. He main- 

 tains (1) that the glow of the female is clearly of longer duration than that of the 

 male ; and (2) that there is an interval of nearly five seconds between the glow of 

 the male and that of the female in response to it. I was unable to distinguish any 

 difference in the duration of the glow in the two sexes at Smithsburg, and the 

 interval between the glows is very little if any over one second. It seems quite 

 remarkable that individuals of the same species should differ so much in their 

 response, especially when there is so little difference in their environment as is 

 found between Washington and Western Maryland. 



