OF THE AMAZON VALLEY. 533 



Genus Napeogenes, nov. gen. 



Head small ; palpi thinly clothed with scales, not hairy, the terminal joint slender and 

 projecting in front of the forehead. Antennae moderately short, and distinctly thickened 

 towards the apex, fore-wing median nervure emitting its first branch at a short 

 distance from the root of the wing, hind- wing lower and middle disco-cellulars running 

 at an obtuse angle with the median nervure ; both of the same length, directed obliquely 

 towards the costa near the apex (a little less oblique in the $ than in the d), straight 

 or very slightly bent, and without recurrent nervules : upper disco-cellular in the cJ 

 rather long, joining the subcostal near its termination ; in the ? short, joining the 

 subcostal far from its termination. The costal and subcostal nervures of the hind wing, 

 in both sexes, are free and wide apart. Fore tibiae and tarsi in the <S aborted ; femur 

 not abbreviated : fore tarsi in the ? slender filiform. 



The species of this genus, such as were then known, were included by Doubleday 

 under his genus Scds ; they are, however, perfectly cHstinct from Sais both in the wing- 

 neuration and in the structure of the fore legs of the <J . Most of the species mimic 

 corresponding species of the allied genus Ithomia, in the same way as the Leptalides do. 

 In every locality where Ithomice are found in abundance, species of Napeogenes are 

 almost sure to be found also, mimicking one or more of them, — the Ithomice being 

 always abundant, whilst their imitators are very generally scarce in individuals. The 

 resemblance between species of the two groups is so great that it is difiicult to imagine 

 it not to be one of real afiinity ; the neuration of the wings, however (a constant and 

 important character), is a sure guide in distinguishing them. They are always represented 

 with this feature carefully marked in the beautiful figures given by Mr. Hewitson in his 

 ' Exotic Butterflies.' 



* Collar and wing-lappets orange ; antennal cluh less abruptly thickened. 

 1. Napeogenes Ctrianassa, Doubleday. 



,Sa7S Cijrianassa, Doubld. and Hewits. Gen. Diurn. Lep. pi. 18. f. 1. 

 Ithomia Cyrianassa, Hewits. Exot. Butt. Ithomia, fig. 65. 



Occurs at Para, in humid parts of the forest, abundantly. It is distributed over a wide 

 area in the Amazon valley, but in each locality it suffers modification. The amount of 

 this modification is not in proportion to geographical distance. Thus, at Fonte Boa, 1500 

 miles to the west of Para, it scarcely differs from the Para type, having only the discal 

 area of the hind wings less transparent ; but on the banks of the Cupari, only 500 

 mil es west of Para (aU these places are in the same latitude), it exists only under the 

 form of a well-marked and constant local variety or race (our N. Adelphe) ; a short 

 distance (150 miles) to the west of Ponte Boa, it occurs again as a distinct local variety 

 (our N. Tunantina). 



The species much resembles, when on the wing, Ceratinia Ninonia, var. Baril. It is a 

 slow flier, and, although abundant in individuals, is confined to limited areas in the 

 districts where it is found. 



