MAYER: COLOR AND COLOR-PATTERNS. 217 
It is quite remarkable that although the genera Melinaea and 
Mechanitis serve as models of mimicry for the Acraeoid Heliconidae, 
they should themselves mimic Ithomia. 
The genus Ithomia is, however, the most independent of all the 
genera of the Danaoid group, and I know of remarkably few good 
instances in which an Ithomia has apparently departed from the 
coloration of its type to assume the guise of the Melinaeas. One good 
example of such a change, however, is afforded by Ithomia fallax of 
Southern Peru, which resembles either Mechanitis methone or Heli- 
conius aristiona of Colombia (see page 210). There is apparently 
a difficulty in ascribing this resemblance to mimicry, for the imitator 
and imitated do not occupy the same geographical regions. 
In direct contrast with the independence of the Ithomias stands 
the case of the genus Napeogenes ; for Godman and Salvin (’79-’86) 
say of Napeogenes, that nearly every species mimics some Ithomia 
which occupies the same district; and thus almost the very existence 
of the genus would seem to depend upon its mimicry of Ithomia. 
It is not the purpose of this paper to discuss, in detail, the numerous 
interesting cases of mimicry which are believed to exist between 
members of the Danaoid Heliconidae. An excellent discussion of 
such cases, and of the relationships of the various genera, has been 
given by Haase ('93*, p. 116-127). 
V. QUANTITATIVE DETERMINATION OF THE VARIATIONS OF THE 
CHARACTERISTIC WING-MARKINGS IN THE ACRAEOID AND 
DANAOID HELICONIDAR. 
(1) Variations of “Inner Rufous” Areas of the Fore and 
Hind Wings. Table 1 gives the color-variations which are exhibited 
by the “inner rufous” area of the fore wings in the Danaoid Heli- 
conidae. This area is marked I in all of the figures upon Plate 4. 
We learn from an inspeetion of Table 1 that this area is rufous in 
color in 124 species of the Danaoid Ieliconidae, transparent in 152, 
black in 24, and that in the remainder it is more or less translucent, 
and of either a yellowish or rufous tinge. 
Table 10 shows the variations which come over the “inner 
rufous” area of the hind wings of the Danaoid Helieonidae. This 
area is marked X in the figures upon Plate 4. It is apparent at 
a glance that the variations which affect the inner rufous areas of 
