MAYER: COLOR AND COLOR-PATTERNS. 
298 
bered that there are 450 species in the Danaoid group ; 25 of 
these belong to the genus Melinaea; yet among these 25 we find 
5 exhibiting this marking as a double spot. Assuming that the 
doubling of this spot has arisen in each species as a sport, and that 
such a sport is as likely to appear in one species as in any other of 
the Danaoid group, then the chances against five such sports 
appearing among the 25 Melinaeas is - ° * 22 x > or a ^ out 
2,880,000 to 1. Indeed, it is probable that all five of the species 
of Melinaea which exhibit the doubling of this spot are descend¬ 
ants of a single ancestor in which it appeared for the first time 
double, for the mathematical chance that one such ancestor should 
appear among the Melinaeas, rather than in any other genus, is 
evidently 1 in or one chance in eighteen. The chance against 
two such unrelated ancestors is, however, 450 x 449 or about 336 to 
25x24 ’ 
1, and the chance against three is 4 -^ ^ 9 ^ 8 , or 6,560 to 1, etc. 
By reference to Table 16 we find that in the genera Heliconius 
and Eueides the inner black area is black or iridescent blue in all 
of the species of Heliconius, but absent in 5 of the 18 species of 
Eueides known to me. These 5 include Eueides aliphera and its 
allies. Now there are 150 known species of the Acraeoid Helico- 
nidae, and 24 of these belong to the genus Eueides; so it is evident 
that the mathematical chance against the supposition that five sports 
arose independently in the genus Eueides, in which the inner black 
was absent, is given by ^^xtaxgi'^xao 146 ’ or 13 > 900 to 1. It is there- 
fore probable that the five Eueides lacking the inner black are 
the descendants of a single ancestor. 
(3) Variations of the “Inner Yellow” and “Middle Yellow ” 
Areas. Tables 3 and 5, and diagram Eig. 98, Plate 9 , show the 
color-variations of the “inner yellow” and “middle yellow” areas 
in the fore wings of the Danaoid Heliconidae. These areas are 
marked III and V, respectively, in the figures upon Plate 4 . The 
“inner yellow” area, it will be remembered, occupies the outer por¬ 
tion of the cell of the fore wing; while the “middle yellow” is found 
in the region just beyond the outer limits of the cell. The two areas 
are often fused together as in Figs. 47, 48, 50, 51, and 55, Plate 4 . 
The inner yellow area is usually smaller than the middle yellow, 
and a comparison of Tables 3 and 5 will show that it is much more 
frequently obliterated by the encroachment of the rufous or black 
