130 NOVITATES ZO C OLOGICAE XXIII. 1916 



to the callosity described under A. insulata. The seventh ste -nite projects into 

 the cavity, the projection being broad, smooth and glossy, v ith the proximal 

 portion longitudinally wrinkled. 



The distribution of the three species suggests that they h ave attained their 

 distinctions by means of geographical isolation and the attending, differences in the 

 surroundings. The most widely distributed species, insulata, lis morphologically 

 the central one, its characteristics agreeing more or less with those which I am 

 inclined to attribute to the common ancestor. 



Ammalo helops Cram. (1775) is another species of wide distribution according 

 to Hampson, I.e., p. 83. I find it to be a composite species, whicli I hope to discuss 

 on another occasion. A. helops is nearly allied to some species placed under 

 Elysius. One of the main distinctions between Elysius and Aminalo in Hampson's 

 Lep. Phal. is the difference in the position of the second subcostal branch of the 

 forewing, this vein being said to arise from the cell in Elysius.' and beyond it in 

 Ammalo. We have, however, a number of specimens of Ammal'o helops in which 

 this vein branches off from the cell. 



Genus Sychesia Möschl. (1877) 



In Hampson, I.e., p. 106, the first section of Elysius i^ characterised as 

 follows: "Sect. I. (Sychesia). Antennae of male with long branches; hindwing 

 with vein 8 absent." One species is placed in this section, Eh'sius dryas Cram. 

 (1775). As this " dryas,''' however, is not a solitary species, but represents a type 

 to wbich quite a number of species conform, there is sufficient r eason for reviving 

 Sychesia as a genus separate from Elysius. 



The species of Sychesia resemble one another very closely in .colour. If in the 

 figure of S. omissus, in Nov. Zool. xvii. pi. 13, fig. 15, the black-larown colour were 

 paler, and the orange of the abdomen and hindwing less bright, tLie figure might be 

 considered a fairly accurate representation of several other species . There are some 

 colour-differences in the various species, but they are as a rule! so vague that a 

 correct determination of the species from mere coloured figures appears to me 

 impossible without recourse to the structure of the tail-ends. In several species 

 there is a conspicuous scarlet tint on the abdomen and collar, bu'fc not in all speci- 

 mens, and this colour may also appear in species which are usually without it. The 

 length of the pectinations of the male antennae is not the same throughout the 

 genus, the males of omissus, for instance, being easily distinguis ned by the short 

 pectinations, and subtilis separated from dryas by the long pectinations. There are, 

 however, other species which cannot be differentiated by the lengt.h of the pectina- 

 tions from dryas or from subtilis. The structure of the tail-encl of the male is 

 rather complicated on account of the many processes and lobt es of which the 

 prehensile organs are composed. A clear view of them is only obtained on removal 

 of the eighth segment ; but for the purpose of identification thiis is hardly ever 

 necessary, the apices of at least some of the processes being visible 1 if the scaling at 

 the tip of the abdomen is partially removed or brushed aside. j The commonest 

 of the species is fortunately not difficult to recognise, and therefore may with 

 advantage serve as a starting-point in the determination of the series of species. 



