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MR. H. W 
upper disco-cellular is very variable, there being a gradation from those species which stand 
nearest to Ceratinia, which have an upper disco -cellular in both sexes, to those approach- 
ing Hymenitis, in which this nervule disappears, the upper radial being then as a branch 
of the subcostal (in the 2) or totally wanting (in the <$). 
2. Hymenitis, part (Doubleday). 
In this series of species the lower radial and upper disco-cellular exist in the <?, 
although the lower radial is more or less aborted, whilst in the $ the upper radial becomes 
joined as a branch to the subcostal, its corresponding (the upper) disco-cellular being 
wanting. The lower radial is removed nearer the costa, terminating at the apex of the 
wing, the median branches being rather widely spread. 
3. Hymenitis, 
The hind-wing lower disco- cellular, in the extreme forms of the group, anastomoses 
immediately with the subcostal in both sexes ; consequently both middle and upper disco- 
cellulars are entirely absent, the lower and upper radials being as branch and sub-branch 
of the subcostal. The median branches are very widely spread, and the wing-cell is 
thrown close to the fore margin of the wing. In the less extreme species, both disco- 
cellulars exist in the 6 ; but they are very short, and the lower radial is always placed 
nearer the subcostal than in group 2. 
The explanation of this diversity in the system of neuration of the hind wing in the 
genus Ithomia seems to be this :— The species exhibit from one end of the scale to the 
other the gradual determination of the nervures towards the costa. In Napeogenes, in 
Ceratinia, in Mechanitis, and still further in Sais, we have seen the radials brought 
within the domain of the median nervure ; in Ithomia they show the opposite tendency, 
namely, to connect themselves with the subcostal system of nervures — a tendency which 
progresses through our sections 1 (Ithomia proper) and 2, and culminates in Hymenitis. 
Hymenitis, therefore, exhibits the extreme development of a plan of wing-neuration totally 
unlike anything existing in the rest of the section Bhopalocera, 
In this direction it may be said to display the type of the beautiful order Lepidoptera 
in its greatest perfection. It is a curious fact that none of the delicate species comprised 
in the subgenus Hymenitis are found in the Amazon plains : they seem to be confined to 
the more elevated valleys of the Andes, in Peru and New Granada, and to the higher 
tropical latitudes of Mexico and S. E. Brazil*. 
* The following described species of Ithomia belong to the Hymenitis section : 
Drury, ii. pi. 7. — Jamaica, St. Domingo. 
Hewits 
New Granada. 
3. I. Theudelinda, Hewits. Exot. Butt. Ithomia, fig. 146. — New Granada. 
4. I. Duillia, Hewits. Trans. Ent. Soc. n. s. vol.ii. pi. 23. fig. 3.— New Granada. 
5. I. Andromica, Hewits. Exot. Butt. Ithomia, fig. 38.— Venezuela. 
6. I. Eruca, Hewits. Exot. Butt. Ithomia, fig. 81.— Brazil, 30° S. lat. 
Morgane 
Mexico 
Hewits 
Nero 
Venezuela. 
Mexico 
10. L Oto, Hewits. Exot. Butt. Ithomia, fig. 39.— Guatemala. 
