BUTTERFLIES OP THE DISTRICT OF COLUMBIA 97 



represent the hibernating form, are probably from eggs laid by the 

 late individuals of the early summer brood. 



Remarks. — The dark summer {dry as) and light autumn {harrisii, 

 pi. 11, fig. 3) forms of this insect differ in the same way as the cor- 

 responding forms of the question mark (P. inter7'oc/atio7iis) , but the 

 differences are not so strongly marked. The dark form occasionally 

 is found early in spring, and the light form is sometimes seen early 

 in summer when only the dark form should occur. 



W. H. Edwards found that this species is three brooded in West 

 Virginia. The first brood is composed of the dark form {clryas) 

 only, the second of both the light and the dark forms, and the 

 third of the light form {harrisii) only. About Boston it is double 

 brooded, the individuals of the summer brood being almost, though 

 not quite, exclusively of the dark form (dryas), while those of the 

 autumn brood are almost without exception of the light form 

 {harrisii). In this region conditions seem to be intermediate be- 

 tween those in Boston and those in West Virginia, but the subject 

 is one for further investigation. 



The Schonborn collection contains four specimens of the light 

 {harrisii) form, one dated September 16 and one October 16, the 

 others undated. The National Museum contains two specimens of 

 this species from Washington, D. C, one, dated June 1, 1911, bred 

 from hop by Dr. W. W. Stockberger, and the other, dated June 5, 

 1900, bred from thistle. 



POLYGONIA PROGNE (Cramer) 

 Gray Cojima 

 Plate 11, Figures 1, 2 



In the Schonborn collection there are four specimens about a label 

 reading ^^ Grapfa jn^ogne (Cramer), Washington, D. C." Of the 

 four specimens two are from New York, one is from Nebraska, and 

 one has no label and is presumabh^ from Washington. 



There is no further indication of its presence in the District, but 

 its occurrence as a rare or temporary resident or as a casual is to 

 be expected, as it occurs southward as far as western North Carolina. 



Genus PHYCIODES Hiibner 



PHYCIODES THAROS (Drury) 



Pe!.\rl Crescent 

 Plate 7, Figures 7, 8; Plate 13, Figure 5; Plate 19, Figure 3 



Occurrence. — Abundant throughout the District and the surround- 

 ing country, being, in fact, the commonest butterfly of the region; 



