MAYER: COLOR AND COLOR-PATTERXS. 215 



diversity of color-pattern an<l very little variation in venation among 

 the species of the Acraeoid group, exactly the opposite condition is 

 met with in the Daiiaoid group, where we find at least twenty 

 different types of venation and only two types of color-pattern. 

 One of these types of coloration is well exemplified Ijy most of 

 the Melinaeas (Fig, 48, Plate 4), and I have therefore called it the 

 " Jl/e/maea" type. The other type is exemplified by most of the 

 Ithomias (Figs. 47 and 52) and has been designated in this paper as 

 the " Ithornia " type. In the Melinaeas, it will be remembered, we 

 find the rufous and black wings crossed by bands of yellow ; while 

 in the Ithomias, on the other hand, the rufous and yellow areas have 

 become transparent, often leaving the wing as clear as glass, and the 

 black, which is so characteristic of the outer half of the wing in the 

 Melinaea type, has shrunk away until it has come to lie along the 

 outer margin of the wing only. 



By a study of all the genera of Danaoid Heliconidae we gain light 

 upon the question of the origin of the 'OTelinaea" and "Ithornia" 

 types of coloration. As we have seen (page 198), the Danaoid 

 Heliconidae are an offshoot from the great family Danaidae. Indeed, 

 two of the genera, Lycorea and Ituna, are so closely related to the 

 Danaidae that Schatz and Rober ('85-92) propose to include them 

 within that family. There can be but little doubt that Lycorea and 

 Ituna are remnants of the ancestral forms which long ago shot off from 

 the Danaidae to f orai the Danaoid Heliconidae ; and it is interesting to 

 note, that in these two patriarchal genera we find the two distinct 

 types of color-pattern which are exhibited by the Danaoid Helico- 

 nidae, for all of the five known species of Lycorea are good examples 

 of the Melinaea tvj^e (see Lycorea ceres, Fig. 46, Plate 4), while the 

 four known species of Ituna all exhibit the transparent, or Ithomia, 

 type of coloration. In fact, in their color-pattei'ns the species of 

 Ituna remind one of gigantic Ithomias. The species of Lycorea, 

 however, are colored very much after the pattern of the Danaidae, 

 and indeed they have departed but little from the tyj^e of the 

 members of the great family whence they sprang. On this account 

 I beheve that the Melinaea type of coloration, which is so charac- 

 teristic of the species of Lycorea, is phylogenetically older than 

 the Ithomia type. 



In order to account for the origin of the Ithomia Xs^q^ avc may 

 assume that, shortly after the primeval forms of the Danaoid Heli- 

 conidae V)egan to segregate out from the Danaidae, the species were 



