70 LEPIDOPTERA INDICA. 



C. No sexual mark on forewing, Hindwing with a sexual patcli, iu male. 



I. Sexual patch on hindwing small. 



a. Exterior margin of forewing uneven, posterior margin of forewing slightly 



convex ............ Trepsichrois. 



II. Sexual patch on hindiving moderate. 



a. Exterior margin of forewing convex, posterior margin of forewing convex . Caluplcea. 



III. Sexual patch on hindwing large. 



a. Exterior margin of forewing convex, posterior margin of forewing very 



convex ............ Euplcea. 



D. One sexual marJc on foreicing. Hindwing ivith a sexual patch, in male. 



I. Sexual mark on forewing short, broad. ; patch on hindwing small. 



a. Exterior margin of forewing convex, posterior margin of forewing slightly 



convex ............ Danisepa. 



II. Sexual mark on forewing short ; patch on himlwing large. 



a. Exterior margin of forewing convex, posterior margin of forewing very 



convex Salpinx. 



h. Exterior margin of forewing oblique, posterior margin of forewing convex Padejima. 



III. Sexual mark on forewing long ; patch on hindwing large. 



a. Exterior margin of forewing oblique, posterior margin of forewing convex Isamia. 



IV. Sexual mark on forewing sleruler ; patch on hindwing large. 



a. Exterior margin of forewing oblique, posterior margin of forewing convex Tiruna. 



E. Two sexual marks on forewing, in male. 



a. Sexual marks long, exterior margin of forewing oblique, posterior margin 



of forewing convex .......... Narmada. 



h. Sexual marks long, broad, exterior margin of forewing convex, posterior 



margin of forewing convex ......... Stictoplcea. 



Difficulty in Disceiminating the Species. — The determination of the species 

 of this group of butterflies, until a verj^ recent period, has been a most difficult task. 

 This difficulty was partly owing to the indefiniteness of many of the original descrip- 

 tions, which were published — mostly without figures — by entomologists having no 

 previous knowledge of the group, and, as has since been shown in the " Mimetic 

 tables" of my "Monograph," published in the Proc. Zool. Society, London, 1883, 

 pp. 208 — 12, this difficulty was intensified by an hitherto unrecognized feature in 

 this group, namely the great superficial resemblance of many of the species to one 

 another; species which, since their division into sections, according to the presence 

 of the sesual mark in the male, are now proved to belong to distinct genera, per- 

 taining to different sections of the group. 



As a result, and chiefly owing to this mimetic resemblance, numerous instances 

 occurred in most collections in which specimens were incorrectly determined, and, 

 moreover, even where the determination of specimens had been made by actual 

 comparison with correctly-named species, several instances came under my own 

 observation in which a series labelled with a given specific name embraced specimens 



