280 ANNUAL REPOBT SMITHSONIAN INSTITUTION, 193 4 



range fly at the rate of 5 or 6 miles an hour, but the smaller individ- 

 uals living farther north fly at the rate of 4 or 5 miles an hour. 



This butterfly is very unsuspicious, and if feeding on a flower in- 

 variably may be captured with the greatest ease. If frightened when 

 in flight, as by the close passage of the net, it usually closes its wings 

 over its back and drops into the grass where it conceals itself, often 

 quite effectively. More rarely it makes off with increased speed in 

 a zigzag flight, but without rising above the usual height. This last 

 peculiarity probably is due to its fear of dragonflies which in great 

 numbers infest the places where it lives. Their plane of flight is 

 higher than that of the bog fritillaries, and although they quickly 

 seize any unlucky butterfly that rises to their level, they will not 

 pounce on anything below them. 



This butterfly is unusually adaptable to changes in conditions. In 

 the vicinity of Boston it commonly first apj^ears in the last week in 

 May, and early in June it has become abundant. A second brood 

 is on the wing in the last week in July, and a third makes its appear- 

 ance in September. In the vicinity of Washington it is not found 

 until about the first of July, and disappears before the end of the 

 month. Here there is only a single brood instead of three broods as 

 farther north. Wh}'^ should a butterfly appear only in midsummer 

 in the South, but fly from spring to autumn in the North? 



Together with this little butterfly there lives another {B. hellona) 

 having almost the same range and commonly found with it, but 

 easily distinguished from it by the absence of silver spots on the 

 under side. This closely resembles the other in its habits, but is not 

 quite so active, though its flight is similarly rapid. The one with 

 silver spots {B. onyrina) is characteristic especially of open grassy 

 bogs surrounded by rough and more or less scrubby pasture land, or 

 of grassy river bottoms, but the one without the silver spots {B. 

 hellona) prefers more uniformly wet localities, particularly the 

 boggy and grassy banks of small streams in hilly or mountainous 

 country, or small wet hillside pastures. 



One of the bog fritillaries {B. astarte) is described as being always 

 found singly on the highest mountain peaks, not below 8,600 feet, 

 far above the timber line. This one is exceedingly shy and difficult 

 to catch. Its flight, especially the flight of the males, is very swift. 

 It rushes and races about over the desolate rocky slopes with the 

 wings constantly in motion, alighting but rarely, and then only for a 

 moment. It is frightened by the least disturbance, and even the most 

 cautious approach of the collector seems sufficient to drive it into 

 precipitate flight. F. H. Dod says of this species that the males 

 play around the extreme summits of the mountains at 8,000 feet or 

 higher. They are very difficult to net, as their flight is exceptionally 



