184 BULLETIN 15 7, U. S. NATIONAL MUSEUM 



o^ Predominantly deep brown or brownish black. 



6\ Wings beyond the position of the innermost black band on the 

 fore wings and the narrow black stripe on the hind wings 

 with the black markings standing out prominently against 

 the lighter background which is dusted with yellow or 

 whitish scales, these becoming most numerous toward the 

 lower margin of the fore wings and the upper margin of 

 the hind wings (pi. 39, figs. 1, 2) No. 6. 



i'. No yellow or whitish scales on the upper surface of the wings 



other than those in the submarginal spots (pi. 40, fig. 1) glaucus. 



There are a number of other forms of the female of this butterfly 

 that have not been found in the District area, though probably some, 

 at least, will be taken here. Several of the forms, so far as I have 

 been able to learn, are of rather limited distribution, while a few 

 are very widely spread. 



An intensive study of this insect based on large numbers of indi- 

 viduals from all portions of its range would probably give results of 

 great interest when compared with the work that has been done on 

 the African P. darda/nus and on certain Asiatic species. 



The several varieties of the female of the yellow swallowtail are 

 herein designated by numbers in order to avoid burdening the 

 already overtaxed nomenclature of the swallowtails with names, 

 some of which would represent stable, but others indefinite and very 

 variable intergrading, forms. 



It should be mentioned that a satisfactory study of the females of 

 this species can only be made on fresh specimens, as the cream-yellow 

 forms gradually change to ochreous in a few months even if kept 

 from the light. 



Spring forms. — The earliest (early April) spring males are very 

 small with the fore wings from 42 mm. to 45 mm. in length. The 

 hair on the thorax and abdomen is very long, and there is a con- 

 spicuous tuft of long hair on the frons. 



On the upper surface the black border of the hind wings is nar- 

 rower than it is in the summer form, and the yellow crescents 

 included in it are larger. The black border of the fore wings is 

 slightly broader anteriorly than posteriorly, the reverse being true 

 in the summer form, and the yellow spots included in it are larger. 

 The black abdominal border of the hind wing is usually much 

 broader than the interspace between it and the cell. 



On the lower surface the dark margin of the hind wings is 

 markedly narrower than it is in the summer form, and its inner 

 border is a straight instead of a scalloped line; it is much more 

 heavily suffused with light scales than it is in the summer form, and 

 the submarginal crescentic spots are very much larger. On the 

 underside of the fore wings the submarginal yellow spots in the black 



