1868. | On the Colour-patterns of Butterflies. 325 
in species belonging to eight of the fourteen families into which 
the butterflies are divided.* (See Plate.) 
The fundamental character of this dark-veined pattern is con- 
firmed by the closeness of the gradations connecting it with others 
apparently altogether distinct. For example, Pieris brassic#, and 
some other insects of the same family, which are wholly white with 
the exception of a broad black tip at the apex of the fore-wing. 
Now several exotic species of Pzeris present the dark veins ex- 
panded at the outer margin of the fore-wing into a deeply scalloped 
black border ; others show the gradual fading of the lower portions 
of the border, together with attenuation of the venous markings in 
the dise of the wing, till the passage from the pattern of P. cratzegi 
to that of P. brassicx# is made by almost imperceptible steps. 
In the genus Hestia, the primary pattern is diversified by a 
great variety of black spots and blotches, which are all evidently de- 
pendent on the venation: the spots occupy a central position between 
the veins, or they are bisected by a false vein, or they are in pairs 
contiguous to a vein. In one fine species there is a broad, black 
band across the wing; but here (as in almost every other instance) 
the outlines of the black markings are strongly affected by the 
veins. We shall see, presently, that this is not the case with the 
brighter colours; but the black markings are very generally thrown 
nearer to or farther from the base by the passage of a vein, as 
geological strata are disturbed by the occurrence of a fault. Even 
where, as in Huplea Tretschkez, only a small spot or two of white 
is shown on the wings, it is pretty plain that the ground-colour of 
the wings is white, almost wholly obscured by a greater develop- 
ment of the dark scales belonging to the veins. 
The scalloped border has been referred to; and as the scalloped 
band, nearer to or farther from the margin of the wing, is one of 
the most prevalent kinds of markings, it may be well to see how 
readily it may arise from the primary pattern. Let it be supposed 
that at a given distance from the base a portion of the dark scales 
begin to diverge on each side from the veins. The dark lines thus 
formed will meet in the middle of the areas between the veins, pro- 
ducing a band of scallops having their concavities towards the base 
of the wing. If the divergence takes place towards the base, scallops 
are formed having their convexities in the same direction. If the 
latter mode of divergence be quickly followed by the former, a row 
of annular markings between the veins 1s the result. In this manner 
may be obtained the simplest and most elementary form of the 
annular or ocellate spot, which in the higher stages of development 
becomes distinguished for its variety and exquisite beauty. Of this, 
more hereafter. 
* Eyen in the less likely families, Nymphalide and Satyridz, it oceurs in 
Penthema Lisarda, Orinoma Damuris, and other species. 
