228 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
variable than the middle. This is only a special case of Bateson’s 
(94) law (p. 185). (f) The position of spots situated near the 
outer edges of the wing is largely controlled by the wing-folds or 
creases (p. 185). 
(9) The scales in Lepidoptera do not strengthen the wings or 
aid the insects in flight. The vast majority of the scales are merely 
color-bearing organs, which have been developed under the influence 
of Natural Selection. The phylogenetic appearance and develop- 
ment of scales upon the originally scaleless ancestors of the Lepi- 
doptera did not alter the efficiency of their wings as organs of flight. 
It is probable, therefore, that this efficiency was an optimum before 
the scales appeared (p. 197). 
(10) A systematic study of the Danaoid Heliconidae demon- 
strates that their color-patterns can be placed in two types. Type 1, 
the more complex, is closely related to the coloration of the Danaidae 
from which the Danaoid Heliconidae sprang, and is therefore, 
phylogenetically speaking, the older type of coloration. This type 
is characteristic of the genera Lycorea, Melinaea, and Mechanitis, 
and I have called it the “ Melinaea” type. It is characterized by 
the fact that the wings are rufous and black in color, and crossed by 
a definite system of yellow bands. Type 2, the “ Ithomia” type, is 
characteristic of the genera Ithomia, Ituna, and Thyridia. The 
“Tthomia” type has been derived from the “ Melinaea” by the 
originally rufous and yellow areas upon the wings having become 
transparent (p. 204). 
(11) The phylogenetic origin of the “ Melinaea” and “ Ithomia” 
types of coloration can be accounted for upon the supposition, that 
when the species of the Danaoid Heliconidae began to segregate 
out from the Danaidae they were for a time rare (p. 215). « 
(12) A record of the characteristic markings upon the wings of 
the Danaoid and Acraeoid Heliconidae shows that, physiologically 
speaking, the colors red, rufous, yellow, and white are closely 
related, and that black is quite distinct from these, being the least 
variable color of all (p. 220). 
(13) In both the Danaoid and Acraeoid Heliconidae, whatever 
color-variation affects that part of the fore wing which is adjacent 
to the body of the insect, almost always the same color-yariation 
affects the homologous area of the hind wing in a similar manner 
(p. 218, and Fig. 99). 
(14) The smaller yellow spots upon the wings of the Heliconi- 
