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 sjiots situated near the 

 outer edges of the wing is largely controlled by the wing-folds or 

 creases (p. 185). 



(9) The scales in Lepidoptera d'o 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 develoj)- 

 ment of scales upon the originally scaleless ancestors of the Lepi- 

 doptera did not alter the efficie)icy 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 Hehconidae demon- 

 strates that their color-patterns can be placed in two tyi>es. 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 ty|)e 

 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 yeUow bands. Type 2, the " Ithomia " type, is 

 characteristic of the genera Ithomia, Ituna, and Thvi"idia. The 

 "Ithomia" t^'pe 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 i*ed, 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-variation 

 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 Helicon i- 



