138 SPOLIA ZEYLANICA. 



very variable insects, and the presence or absence of one or more 

 spots in the basal half of the discoidal cell (on under side) is a charac- 

 ter of no specific value. There is, however, one constant character 

 by which they may be distinguished. In the so-called hecabe, the 

 black border of the fore wing involves that portion of the inner 

 margin, while, in our silhetana, a thin yellow line is continued along 

 the inner margin, below the black border, towards the outer angle. 

 In the males of silhetana, the black border is often very narrow and 

 without any appreciable expansion at its lower end. I have never 

 observed this restricted border in any of the forms of our hecahe. 

 A chocolate patch — of var3dng dimensions — may occur at or near 

 the apex on the under surface of the fore wing in females of both 

 species. 



In the hecabeoid group we find two distinct types of larvse : 

 one gregarious, with a black head, which produces what we — in 

 Ceylon — regard as silhetana ; the other non-gregarious, with a green 

 head, from which results our supposed hecabe. 



The nomenclature of these species is still in great confusion, and 

 every fresh authority maintains a different opinion to that of the last. 

 Piepers, in his " Rhopalocera of Java," describes the larva of 

 hecabe as having a black head. According to the same author, the 

 larvse of sari are gregarious, but have green heads. Moreover, he 

 does not recognize silhetana as distinct from hecabe ; but his hecabe 

 is probably not the same as ours. The British Museum authorities 

 again assert that hecabe does not occur in India or Ceylon, but is 

 confined to the Chinese region. They recognize our Ceylon insect as 

 T. suava. Col. Manders remarks of the typical examples of hecabe 

 and suava displayed in the British Museum collection : "If the 

 labels were removed, I would defy any one to differentiate between 

 them." Swinhoe, I understand, is describing all the innumerable 

 forms of hecabe as distinct species. These many conflicting opinions 

 do not tend to make matters clearer for us. Who is to be the final 

 authority ? 



E. ERNEST GREEN. 



Supplementary Note. — When preparing the drawings shown on 

 the accompanying plate, illustrating the colour pattern in different 

 forms of Terias silhetana and hecabe, I noticed two other distin- 

 guishing characters which appear to be constant for the two species 

 (as represented in Ceylon). 



In silhetana the outer margin is distinctly crenulate, while in 

 hecabe the same margin is practically entire. By this character 

 alone I have been able to separate — with certainty — the two species 

 by examination with transmitted light without removing them from 

 their paper envelopes. 



In hecabe the black border is continued along the costal margin, 

 gradually thinning out before reaching the base of the wing. In 



