what was once a very rare variety or aberration. Secondly, it is well to 
remember that both Pzeris rapa and P. venosa have yellow aberrations, 
and even possibly (as I have argued in ‘‘Enromoxoaist,” 1888, p. 112, ) 
came from yellow ancestors,—and thirdly, in one species at least of 
Anthocharis (A. cardamines) there is an aberration (ab. aureoflavescens, 
see “Enromoocist,” 1888, p. 189), in which yellow takes the place of 
orange. 
Preparatory stages. —Dr. T. A. Chapman has an excellent paper 
(‘‘Enr. Mo. Mae.,” 1888, p. 257), in which he compares the egg of A. 
cardamines with that of Prerts rape—pointing out that the egg of the 
former becomes orange, while that of the latter is never darker than a 
pale yellow—and further, that the eggs of cardamines are laid on the 
flower-heads. Having the eggs of no other Prervs at hand, he goes no 
further with his comparison, and it migbt be supposed that these differ- 
ences were in some sense generic. But it is not so: Prerts profodice is 
very common in Custer Co., Colorado, and lays its eggs profusely on 
Arabis, Sisymbrium and other cruciferous plants. These eggs are orange, 
and are nearly always laid on the flower-heads of Arabis, though also 
frequently on the stem and leaves of Szsymbrium. 
Anthocharis ausonides (var. coloradensis, H. Edw.) flies here in 
May, and lays its eggs in the same situations as P. profodice. ‘This year 
I sent Mr. W. H. Edwards a number of young larva, presumed to be 
those of profodice—and certainly seeming all to belong to the same 
species. But on the 1st of July he wrote: ‘Out of my profodice larve I 
got on the 30th (June) several proper pupz (a pr olodice emerged from 
one of them some days later) and one of Anh, ausonides. 1 had not 
noticed any difference in the larve: I thought sometimes some were 
blacker than others—more black hairs.” So it will be seen that in the 
earlier stages P. profodice and A. ausonides have the closest resemblance 
—the larvae, in fact, are not distinguishable. 
From these facts, I am inclined to believe that An/hocharis ausonides 
on the one hand, and Prer?s profodice and its allies on the other, come 
nearest to the primitive stock from which 1 it is favorable 
to the idea of the antiquity of awsonides that it is the one species of its 
genus in America ranging to the far north—even Alaska. Assuming this, 
we are perhaps at liberty to construct a hypothetical Prosopierss, and 
imagine a butterfly inhabiting the American continent ages ago, in shape 
somewhere between the modern Pieris and Leucophasia—perhaps doubie- 
brooded—in markings, with a central black spot and dark apical patches 
to the fore wings, on the underside gray, marbling on the secondaries 
(for the green I take to be a subsequent arrangement of the yellow and 
black scales*)—in color, possibly saffron or brimstone yellow, though 
probably already white, or partly so. 
West Curr, Custer Co., Cororapo, July, 1888 
* And the green veining of the underside of Pieris napi is of the same nature— 
in neither case is there really any green pigment. 
