BUTTEEFLIES OF THE DISTRICT OP COLUMBIA 103 



must have made its first appearance very shortly before, if not 

 actually on, the date of capture. On July 4, 1929, two were seen, 

 but were not caught. On Jul}^ 13, 1929, eight were caught in the 

 course of the afternoon, about half of them much worn. On July 17 

 the bog was visited in company with Dr. G. W. Rawson, of Detroit, 

 Mich., and five were caught and two more seen in the course of half 

 an hour. The first specimen captured was taken July 15, 1928, by 

 the side of the road, but in that year the curiously restricted area in 

 which alone this butterfly is found was not searched. 



In the vicinity of Boston, Mass., this insect usually first appears in 

 the early part of the last week of May, and it becomes abundant early 

 in June. Mr. Lintner reported it as abundant at Albany, N. Y., on 

 May 16, and Mr. Scudder took it there on May 17. It is reported 

 from Ottawa, Ontario, on May 22. 



In New England there is a second brood which appears in the last 

 week in July, and as early as the first week in July in Nantucket. 

 The butterflies of this brood are on the wing before those of the first 

 brood have disappeared. They continue to emerge through a part 

 of August, and, according to Mr. Scudder, are found on the wing in 

 September, when the individuals of the third brood have made their 

 appearance. 



The silvered bog fritillary thus first appears in the vicinity of the 

 District a full month later than it does in the vicinity of Boston and 

 of Ottawa, and nearly six weeks later than at Albany. Still more 

 interesting is the fact that in this vicinity there is only a single brood 

 instead of the three broods found in New England. 



The region where it occurs locally is subject to flooding in spring 

 with the presumable frequent submergence of the caterpillar, which 

 may account for the late appearance. Late in summer the locality 

 becomes very dry, so that probably the caterpillars estivate, estiva- 

 tion and intermittent feeding being followed by hibernation. This 

 would prevent the appearance of any but early and midsummer 

 imagos and eliminate late-summer and autumn broods. 



The three other butterflies especially characteristic of the area 

 where the silvered bog fritillary occurs [Satyrodes eurydice, Atrytone 

 pontiac^ and PocDnes niassasoit) are similarly single brooded. 



Remofrks. — This is not a very conspicuous insect, and unless one 

 is especially on the watch for it it is likely to escape notice. It is 

 very easily mistaken for a yellow dragonfly, just as Euphydryas 

 phaeton is easily mistaken for a black-winged dragonfly. 



Its flight is direct and rather fast for such a small butterfly, most 



nearly resembling that of Euptoieta claudla, but less nervous. It 



progresses by a series of flaps alternating with glides at the rate of 



5 or 6 miles an hour, maintaining a uniform height of from 2 to 6, 



66544—32 8 



