1258 
that direction), darker or lighter hue of one and the same colour, 
sharper or more effaced traces of the same design. 
This phenomenon is a necessary consequence of a general fact, 
which L was able to establish by comparison of the different indivi- 
duals and sexes of the same species, as well as by that of different 
species belonging to the same genus, or by the genera among them- 
selves, viz. that the colour-pattern of all Hepialids can be deduced 
from one ground-form, or, expressing it in evolutional terms, that 
all Hepialid wing-markings have developed as modifications of the 
same original form. 
Now on reconstructing the latter, it is found to conform to the 
rules, formulated for the original colour-pattern of Lepidopterous 
wings in general. Lt consists of a regutar alternation of biconvex 
and biconcave markings, filling up the interspaces between the wing- 
veins and rigorously keeping within these boundaries. This arrange- 
ment is uniformly repeated on fore- and hindwings, upper- and 
underside, yet there exists a considerable contrast between the 
upper side of the forewings and the rest of the wing-surface, in so 
far as the former shows the markings sharply delineated and vividly 
coloured, while on the remaining wing-surfaces they are faint and 
diluted, often almost effaced. This may go so far, that only by 
observation of the wing-surface under a very oblique angle, or by 
careful inspection of photographs, the presence of spots on an 
apparently unicolorous surface can be detected (in the same way as 
the characteristic pantherine pattern can be distinguished on the 
skin of the black leopard by looking at it under a very acute angle). 
I must acknowledge, that for want of material up to this moment 
[ have not been able to investigate the development of the Hepialid 
wings in their pupae and so to give additional proof of the primitive 
character of their colour pattern. Neither have | succeeded in dis- 
covering traces of markings on the pupal wing-sheaths. 
In some species the above mentioned primitive colour-design is 
present in its entirety, in others it is more or less modified and 
reduced to fragments. The modifications are different in character : 
sometimes the entire wing-surface has been uniformly influenced by 
them, e.g. when the markings have disappeared and one single hue 
prevails. In other cases part of the surface has deviated from the 
original plan, while this has remained unaltered on the rest of the 
wing, in which case the proximal part usually Shows the modified 
plan, the distal one the original design. Judging by the complication 
or simplicity of the design, a distinction between progressive and 
regressive changes may be made. 
