108 BULLETIN 15 7, U. S. NATIONAL MUSEUM 



At Waynesburg Mr. Baker found that in 1930 this species first 

 appeared on June 21. 



Season. — ^The regal fritillary first appears after the other large 

 fritillary {Argynnis cyhele) has become common. The earliest indi- 

 viduals, which are males, are on the wing about the middle of June. 

 Their number slowly increases, and females begin to appear about 

 the first of July. About the middle of July the males have all, or 

 nearly all, emerged, but the females continue to increase in numbers 

 until about the middle of August. At this time the males, though 

 still abundant, are all more or less rubbed and worn. They remain 

 common, however, throughout August and are seen in diminish- 

 ing numbers until about the last week in September, when they 

 entirely disappear. Toward the middle of September the females 

 become more active than they have been previously, cease feeding 

 on flowers, or at least feed very much less than before, and devote 

 themselves to depositing their eggs. They may be seen thus occu- 

 pied, in diminishing numbers, until at least the middle of October. 



The regal fritillary seems to differ from the other two large 

 species in this region {Argynnis cyhele and A. aphrodite) in that 

 the butterflies emerge continually from their first appearance until 

 the end of the season, and there is no difference between the earlier 

 and later individuals. 



Remarks. — Compared with specimens from Essex, Essex County, 

 Mass., specimens from the District are larger, the smallest of the lat- 

 ter being larger than the largest of the former. The increase in 

 size is more marked in the females than in the males, the average 

 length of the fore wdng being 3 mm. more in District than in Essex 

 County males, while the difference in the females from the two 

 localities amounts to 5 mm. The difference in the average length 

 of the fore wing between males and females from Essex County is 

 8 per cent of the average wing length of the males, while in the 

 District this difference is 12 per cent of the average wing length 

 of the males. Measurements of si^ecimens from the two localities 

 are as follows : 



LENGTH OF FORE WING OF ARGYNNIS IDALIA 



Males: Essex County, Mass. (6) 36-40 mm., averaging 38 mm.; District of 



Columbia (5) 39-42 mm., averaging 41 mm. 

 Females: Essex County, Mass. (3) 42-44 mm., averaging 43 mm.; District of 



Columbia (16) 4&-50 mm., averaging 48 mm. 



In color the District males are usually brighter than the northern 

 males, but in the females the difference is imperceptible. In both 

 sexes the black markings tend to be slightly heavier in northern 

 examples, and the dark color near the inner border of the hind wings 

 on the underside especially is more extensive. 



