(_Male._) Papilio Hersilia. Cramer, _pl._ 173. C. D. ---- argante. _Fab. Ent. Syst._ iii. _pt._ 1. _p._ 189. Colias argante. _Godart in Encycl. Method._ 9. 92. _no._ 11. (_Female._) Papilio Cipris. _Cramer_, _pl._ 99. E. F. Colias Cnidia. _Godart_, 93. _no._ 14. * * * * * No two insects can present a more striking dissimilarity than the sexes of this species; and it was only after a considerable degree of attention to the subject, in their native climate, that we were at last thoroughly convinced that _Colias argante_ and _C. Cnidia_ were, without the least remaining doubt, the male and the female of one species. I have had the same opinion communicated to me by my friend Dr. Langsdorff, whose long residence and observations in Brazil render his opinion of no small authority. As both insects are well known, and their distinctions given in the specific character, it will be only necessary to observe, that the under surfaces of the wings in both sexes vary much both in the density of the minute dots, and short undulated stripes that spread over their surface; and that the silvery spots in some males are strongly marked, and in others quite obsolete: there is, in very fine individuals of this sex, a faint bloom of pink spread on the orange of the upper surface, which heightens the vivid yet chaste beauty of the insect. The females are not so common. I met with them both in northern and southern Brazil, and have seen them in collections from Para directly under the equinoctial line. * * * * * Pl. 53 [Illustration] STROMBUS cylindricus. _False Scarlet-mouthed Strombus_--_Upper and under figures_. * * * * * GENERIC CHARACTER.--See Pl. 10. * * * * * SPECIFIC CHARACTER. _S. testa coniformi, spira brevissima ad basin depressa, anfractibus convexis inaequalibus, labio exteriore supra lobato, intus striato; interiore sub-obsoleto, albo._ Shell coniform; spire short, depressed at the base, the whorls convex and unequal; outer lip lobed above, and internally striated; inner lip nearly obsolete, white. _Lister_ 850. 5. (bad.). _Gualt._ 31. 1. _Knorr_, vi. _tab._ 15. 3. Strombus luhuanus _Linn._ _Martini_, x. _tab._ 157. 1499. 1500. Young. Lip above entire, inside smooth, whorls tuberculated. _Lister_, 849. 4. a? _Knorr_, vi. _tab._ 17. 2. * * * * *