TEHIAS. 253 



margin, but is always linear and extended preapically downwards 

 from the costa. In T. silhetana and its varieties, on the contrary, 

 it is always large, well developed, and extends, though often some- 

 what diffusely, to the very edge of the termen below the apex, as 

 in the dry-season specimens of T. sari=T. sodalis and T. ander- 

 soni, Moore, which latter two forms, however, differ in the 

 markings of the upperside of the fore wing. 



Like all wide-ranging forms T. hecabe varies enormously, and 

 consequently has received a host of names. The descriptions above 

 of the imago are taken from specimens picked to match the figure 

 given in Edwards's ' Gleanings of Natural History,' which, accord- 

 ing to Professor Aurivillius (' Eecensio critica Lepidopterorum 

 Musei Ludovicse Ulricse,' 1882, p. 60), represents the typical form 

 of " Papilio hecabe," Linne. 



Taking the varieties seriatim we have 

 T. suava, Boisduval, T. hecabeoides, Me'netries, 

 T. nicobariensis, Felcler, and T. kana, Moore 

 (fig. 61), all of which differ so slightly from 

 typical hecabe as to require no separate 

 description. The difference is chiefly one of 

 the width or heaviness of the black markings 



on the uppersides of the fore and hind 



Fig. 61. Tcrias wings. The dry-season forms of these are 

 hecabe, var. kana. T. simulata, Moore, and T. contiibernalis, 



Moore. 



Var. merguiana, Moore (fig. 62 a, p. 254), is a wet-season form 

 which differs from hecabe, chiefly in the inner margin of the dilated 

 posterior tornal portion of the black area on the upperside of the 

 fore wing. This in hecabe is slightly excavate or vertical, in mer- 

 fjuiana sloped obliquely outwards. The dry-season form of this is 

 T. excavata, Moore, from which T. fraterna, Moore, is practically 

 inseparable. 



Var. purreea, Moore = var. patruells, Moore (fig. 62 c) and var. 

 swinhoei, Butler (fig. 62 d), were all described from dry-season 

 specimens, and show a diminishing width of black area on the 

 apex and termen on the upperside of the fore wing and an 

 increasing irregularity in the outline of the inner margin of the 

 same, till in T. fimbriata, Wallace=2'. narcissus, Butler, and T. 

 irreqularis, Moore = T. asphodelus, Butler (fig. 626), the inner side 

 of the black area becomes more evenly curved, though the actual 

 outline is still somewhat sinuous and often irregularly dentate. 

 The varieties with the least amount of black on the upperside of 

 the fore wing are T. simplex, Butler (fig. 62 e) and T. apicalis, 

 Moore (fig. 62/). 



It must be remembered, however, that from the many variations 

 of T. hecabe at all seasons, certain specimens can be picked out and 

 be said to represent the wet-season forms of the insects I have 

 here ranked as mere varieties. Such selection is in my opinion 

 entirely arbitrary and negatived by the results of breeding, so 

 far as reliable experiments iu this latter have been undertaken. 



