( X ) 



" The specimens sent in illustration are five govindra from 

 Mussoorie (4500 ft., Apr. 22, 1907), one govindra from Murree 

 (6000 ft., Apr. 29, 1898) and one typical agestor from the 

 Khasia Hills (1908). The first six are arranged to show a 

 gradual transition in the development of the diagonal mark- 

 ing across the f.-w. cell and in the filling up basally of area 5 

 in the f.-w. with black, in mimicry of area 4 in the model 

 tytia. The same series also shows the cutting off by a black 

 lunular line of a row of submarginal spots from the Papilionine 

 streaks in f.-w. areas 1-4 to match those in tijtia. 



" A series of the model D. tytia — one from Chakrata (Sept., 

 1893), four from Tehri Garhwal, near Mussoorie (May 1-8, 1907) 

 — has been arranged to show the gradual disappearance of 

 the black lines separating the discal and postdiscal spots in 

 f.-w. areas 2 and 3, thus matching the streaks in agestor. 

 The three characteristic spots in areas 2 and 3 of this Danaine 

 group (conf. melanea, Cram., aglea, Cram., and melanoides, 

 Moore, sent herewith) and the Papilionid streak have thus by 

 reciprocal variation become a spot and a streak in the inter- 

 spaces of both species, the Papilio producing a submarginal 

 spot out of the end of its streak, the Danais producing a 

 streak by the fusion of its discal and postdiscal spots. 



" Some of the imperfections, due to difiiculties of structure, 

 etc., seem almost more interesting than the perfections. 

 D. tytia, in reducing the black pigment, has lost the streaks 

 in the interspaces, common to both families, and fairly pro- 

 minent in agestor. The difference in the arrangement of the 

 median and discoidal nervules seems to be a cause of cross- 

 purposes. Agestor is filling f.-w. area 5 with black in imita- 

 tion of area 4 of tytia, while tytia seems to be clearing area 4 

 in imitation of the same area in agestor. On the hind-wing 

 the difference in size of the respective cells seems to be the 

 cause of a great deal of variation in the proportion of reddish 

 colouring. Papilios and Pierids seem to have considerable 

 difficulty in accurately copying the markings about the 

 cJ Danaine scent-glands; Nymphalines are much more 

 successful. 



" Calinaga buddha, Moore, appears to be an outlying mem- 

 ber of the tytia-agestor combination. It has no red on the 



