XXll 



black hairs similar to those marking the courses of the other well-developed 

 nervures. In many other cases there is scarcely anything of the missing 

 vein (Ic) to be seen, but its former existence is indicated by the markings 

 of the wings, which make the cell between the veins 1 /; and 2 appear double. 

 In other cases this indication of the original state is also lost, and the cell 

 which was formerly double shows the same number of spots as the others. 

 The wing-cell in question, as in Thyridia, still appears double in Dircenna, 

 Ceratinia, Mechanitis, MelincBa, and in all the allies of the Ithomiae ; on the 

 other hand it is single in Lycorea and Danais, as in Ituna (and also, judging 

 from figures, in Hestia and Euplaa). 



" A second distinguishing character between the genera Ituna and 

 Thyridia consists in the presence of a small 'basal (teW {Wurzelzelle), as 

 Herrich-Schaffer calls it, at the base of the hind-wing in Ituna, and also in 

 Lycorea' and Danais, but which is wanting, on the other hand, in Thyridia 

 and in all the allies of the Ithomise. Herrich-Schaffer made use of the ' basal 

 cell,' where he found it, as a family character. Thus, by its absence or 

 presence, he distinguishes between the families Heliconidse and Dana'idae, 

 which latter he limited to the genus Danais; if he had not therefore over- 

 looked the certainly very small ' basal cell ' in Ituna and Lycorea, he would 

 have separated these genera from the Ithomiae and have associated them 

 with Danais. 



Fig. 3. Fig. 4. 



Basal portion of the hind-wings of Ituna Ilione (Fig. 3) and Thyridia 



Megisto, ^ (Fig. 4). 



PC, precostal; C, costal; SC, subcostal veins ; WZ, basal cell. 



" Tn the next place, in the production of odour, the male Thyridia allies 

 itself to the Ithomiae, Ituna to Lycorea and Danais. The males of Ithomia 

 and its allies are known to possess an odoriferous ' tuft of hair on the upper 

 side of the hind-wing on the subcostal vein " (Herrich-Schaffer), and this 

 character served that author for distinguishing the genus. In Thyridia 

 Megisto the odour of this tuft is very powerful, and it is the only species 

 known to me in which the character acquired by the male has been trans- 

 ferred to the female ; in the latter it is certainly much less developed and 

 emits a weaker odour. In Ituna this tuft is wanting on the hind-wings : 

 on the other hand, as shown by Doubleday, the males have two finger-shaped 

 processes at the end of the abdomen, which can be protruded and withdrawn 

 at pleasure. They carry a tuft of stiff black hairs, which can be spread out 

 like a round brush, and emit what appears to me to be a strong repugnant 



