XXI 



show, like the Ithomise, a preference for the small white flowers of an 

 Adenostemma , which grows on the borders of woods and on the edges of 

 forest-paths; but they also visit other flowers, especially white ones, of the 

 same order (Compositse), sucli as Venionia, Mikania and BaccJuiris. I do 

 not remember to have seen them on flowers of other orders. 



" The characters by which Doubleday separated the genus Ituna from 

 the apparently similar Methoiia and Thyrldia are such as would not prevent 

 these genera from being regarded as most closely related, and the differences 

 to which I am about to refer may appear very insignificant; they become 

 of importance, however, from the fact that they recur in long series of allied 

 species, one group of which agrees with Ituna and the other with Thyridia ; 

 it thus appears that the Danaidre long ago underwent separation into two 

 groups, one being related to Ituna and the other to Thyridia, so that these 

 two genera must have undergone a correspondingly ancient separation. 



Fig. 2. 



Jer side. 



Fig. 1. Wings of Ituna Ilione, S' 

 Fig. 2. Wings of Thyridia Megisto, ^ 

 The wing-veins are numbered according to Herricb-Schaffer's system. 



I Un 



" In the next place, on the hind wings in both sexes, between two of the 

 veins, there are always two white spots situated between the nervures 

 1 b and 2 (/. e., between the submedian and first branch of the median), but 

 in Thyridia these spots are double. The wing-cell between these two 

 nervures appears double, as indeed it is. Originally, as shown by motlis 

 and the pupse of butterflies, the wings of butterflies had three veins on the 

 inner margin, the foremost of which (Ic) has disappeared, although some- 

 times to be found in a rudimentary condition. Thus, in Acra:a Thalia, for 

 example, the course of this vein on the hind wing is indicated by a row of 



