BUTTEEFLIES OF THE DISTRICT OF COLUMBIA 143 



mon about the rocky cliffs on the Virginia side of the Potomac oppo- 

 site Pliimmers Island. 



I did not meet with this species until 1931, when I found it rather 

 common along the edges of the woods bordering Paint Branch, and 

 fairly frequent in the bogs and other open places in the Avoods. 



There is a specimen in the Yale University Museum collected by 

 Charles R. Dodge in the District and recorded by Mr. Scudder in 

 1889, and another in the National Museum taken by Dr. G. P. 

 Engelhardt on the Virginia side of the Potomac opposite Plum- 

 mers Island on May 11, 1920. 



Season. — I found this species most common on April 29, the first 

 day on which I was so fortunate as to meet with it. About a dozen 

 were seen, and 4 worn specimens, 1 male and 3 females, were cap- 

 tured. Other worn and broken females were taken on May 3 and 

 May 9. Doctor Engelhardfs specimen, taken on May 11, is fresh. 



The butterfly probably appears in March or early in April and 

 flies until about the middle of May. 



Mr. Scudder says that in New England this species always pre- 

 cedes /. irus by a few days in places where both occur, and Messrs. 

 Cook and Watson say that in New Jersey it appears from a week to 

 10 days earlier than either /. inis or /. henrici. It doubtless precedes 

 these species by a week or so in the District, although we have no 

 definite records. 



HaUts. — Mr. Scudder said that this butterfly prefers rocky heaths 

 where Vaccinium and other low shrubs grow in patches, and is fond 

 of alighting upon rocks or upon dead twigs lying on the ground. 

 Dr. Walter Faxon has noticed that it is partial to Antennaria. 



In the vicinity of Boston I have found it abundant about lichen- 

 covered rocks in woods with numerous pines and Vaccinium, where it 

 flies with the various species of Thanaos. Doctor Engelhardt found 

 it here amidst similar surroundings. 



Each season I have searched for it about the rocks and cliffs on 

 the Maryland side of the Potomac, but have never found the slightest 

 trace of it. 



On April 29, 1931, when searching for salamanders in company 

 with Dr. and Mrs. Torsten Gislen, of Uppsala, Sweden, and Miss 

 Doris M. Cochran, I most unexpectedly came across this butterfly 

 in some numbers along the borders of the woods in the Paint Branch 

 Valley, and also found it in the bogs and other open places in the 

 woods. Though pines and Vacdnium are abundant here, there are 

 no bare rocks. As usual, it was flying with large numbers of several 

 species of Thanaos, especially T. juvenalis, T. horatius, and T. hriso. 



This little butterfly has a rather feeble, slow, and fluttering flight 

 and, as Mr. Scudder says, seldom rises more than a foot or two above 

 the ground even when alarmed. It is unusually sluggish for a hair- 



