MAYER: COLOR AND COLOR-PAITERNS. 217 



It is quite remarkal)le tliat altliough the genera ^lelinaea and 

 Mechanitis serve as models of mimicry for the Acraeoid Hehconidae, 

 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 feAV good 

 instances in which an Ithomia has aj^parently departed from the 

 coloration of its tyj^e 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 Xapeogenes; 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 Ileliconidae. 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 Heliconidae. 



(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 inspection of Table 1 that this area is rufous in 

 color in 124 species of the Danaoid Heliconidae, 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 Heliconidae. This 

 area is marked X in the figures upon Plate 4. It is apparent at 

 a glance that the variations Avhich affect the inner rufous areas of 



