365 



Pie RI D.E. 

 Picris brassicœ (fig. 8). 



Of the four species of Pieridce whose pupae I was able to 

 study, P. brassicœ seems to me the fittest to prove the funda- 

 mental identity of the wing-sheath pattern in different families 

 of Rhopalocera. The dark pigment is restricted to the course 

 of the veins and the median stripes of the interveinal spaces. 



Along the veins the black pigment is distributed at unequal 

 distances in isolated rounded spots of dift'erent size, wliich, 

 towards the outer margin, get more alike and become arranged 

 in parallel transverse rows. The interveinal pigment, on the 

 contrary, is concentrated in numerous irregular little ripples, 

 mostly running transversely, and more or less arranged in the 

 grotesque, spider-like markings airead}' known to us from the 

 VanessidcE. These markings nearly fill in the whole space of 

 the wing-cells, no inner series of light-coloured, polished spots 

 being discernible. In another point, however, the pupa of 

 P. brassicœ shows a certain likeness to that of both Nymphalidœ 

 and Papilionidœ : its lateral wing-margin (along the border- 

 line of the imaginai wing) bears a row of triangular black spots, 

 situated between the veins. These spots may be considered as 

 homologous to the pigment-accumulations around the white 

 marginal tubercles of the Vanessidœ and the Papilionidœ ; 

 these latter structures themselves being absent in the Pieridœ, 

 as is also the inner series of light spots. 



That the latter may have been present in the ancestors of 

 Pieridœ is rendered probable by the wing-sheath of Goncptcryx 

 rhamni (fig. 9). In the light-green ground-colour of this pupa, 

 a faint pattern of darker pigment may without difficulty be dis- 

 tinguished, especially in the first hours after exuviation. The 

 pigment-arrangement in the wing-cells bears a great resemblance 

 to that of P. brassicœ, but that along the veins is almost absent. 

 At a certain distance from the imaginai wing-margin, however, 

 the dark pigment-figures end with a taint concentration around 

 a light centre : our inner marginal series of light spots ! The 

 same phenomenon is repeated at the above-mentioned margin 

 itself : here also the dark interveinal spots show a lighter centre. 

 Asimilar dark, circumscribed mark, even more conspicuous than 



