MAYER: COLOR AND COLOR-PATTERNS. 225 
There is, apparently, but one important respect in which the 
Danaoid Heliconidae are more variable than the Papilios, and that 
is size. For example, Lycorea ceres, which is probably the largest 
of the Danaoid group, has 2.2 times the spread of wing of Ithomia 
nise, which is one of the smallest (see Plate 4, Figs. 46 and 54). 
The largest Papilio, P. androgea, on the other hand, spreads only 
2.16 times as much as the smallest, P. triopas. 
There is another minor respect in which the color-patterns of the 
Papilios are different from those of the Heliconidae. In the Heli- 
conidae the fore wing slightly overlaps the hind wing, and that por- 
tion of the hind wing which is hidden from view is always dull in 
color (see Plates 5-8). In the Papilios, however, the fore wing 
does not overlap the hind wing to such an extent as in the Helico- 
nidae, and it is worthy of note that the costal edges of the hind 
wings in the Papilios are as brilliantly colored as are any other por- 
tions of the wings. 
It is difficult to account for the remarkable conservatism in respect 
to color-variations among the Heliconidae, unless we resort to the 
explanation afforded by the theory of mimicry; for, while there is 
such remarkable simplicity and uniformity of color-pattern through- 
out the whole group of the Heliconidae, individual variations 
are very common, In the collection at the Museum of Compara- 
tive Zodlogy, for example, one finds a regularly graded series of 
specimens of Heliconius eucrate; at one end of this series the 
“inner rufous” area of the hind wing is bright yellow, and at 
the other end it is rufous; intermediate specimens are found in 
which this area is yellow, but dusted over with rufous scales. Also 
the “middle black band” of the hind wings in Melinaea parallelis 
is very variable, some specimens showing it broken in the middle 
(Plate 7, Fig. 82), and others haying it as an entire band, I have 
also seen one specimen of HH. burneyi in which the commonly 
yellow spots upon the under surface of the wings were changed to 
white. Another good instance of individual variability is afforded 
by H. phyllis (Plate 5, Fig. 65), for in this species the series of 
small red spots sometimes found just below the yellow band upon 
the hind wing is very variable, and more often absent than present. 
Still other instances of individual variability are seen in the yellow 
stripes upon the wings of FH. charitonius (Plate 5, Fig. 64), which 
are often found tinged with rufous. Also the remarkable diversity 
in Mechanitis polymnia, and M., isthmia (Plate 7, Figs. 84-87) are 
