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. Antenna} 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 <?), straight 
or very slightly bent, and without recurrent nervules : upper disco-cellular in the d 
rather long, joining the subcostal near its termination; in the 2 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 6 aborted ; femur 
not abbreviated : fore tarsi in the ? slender filiform. 
The species of this genus, such as were then known, were included by Doublcday 
under his genus Sais ; they are, however, perfectly distinct from Sais both in the wing- 
neuration and in the structure of the fore legs of the 6 . Most of the species mimic 
corresponding species of the allied genus Ithomia, in the same way as the Leptalides do. 
In every locality where Ithomia 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 difficult to imagine 
it not to be one of real affinity ; 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 
1 Exotic Butterflies. ' 
* 
Collar and wing-lappets orange ; antennal club less abruptly thickened 
1. Napeogenes Ctrianassa, Doubleday. 
Sais Cyrianassa, 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 Ponte 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 
miles west of Para (all these places are in the same latitude), it exists only under the 
form of a w^ell-marked and constant local variety or race (our N. Adelphe) ; a short 
distance (150 miles) to the west of Fonte Boa, it occurs again as a distinct local variety 
(our N. Tunantina). 
The species much resembles, when on the wing, Ceratinia Ninonia, var. Barii. It is a 
slow flier, and, although abundant in individuals, is confined to limited areas in the 
districts where it is found. 
