Full. 21. VII. 1934. 
ZYZYPYGE; VESOOA. By Walter Hopp. 
1073 
III. The subcostal vein is free, connected at most with the cell by a bar: Aidinae. 
The $$ of the Aidinae and Trosiinae exhibit the same course of the subcostal vein as in the $3. It 
varies, however, in the $$ of the Megalopyginae-, it is like that of the AS in few species, but in most of the 
species it is like that of the Trosiinae. In phylogenetic respect the free subcostal vein of the Aidinae effecting 
an invigoration of the costal margin of the wing is the most advanced, the anastomosing subcostal vein of the 
Trosiinae the most retarded, while in most of the Megalopyginae it is explicable as a conservative element in 
the females, as a progressive element in the males. 
Among the Trosiinae there are yet in other respect the most generalized Megalopygidae, i. e. in the 
organization of the 10th ventral segment of the AS- In Norapella bi'pennis it is preserved as a complete ventral 
segment with paired appendages on the sternit and tergit. Step by step a simplification of this organization 
can be followed up, till finally, in certain species of Norape, a single small lobe of the tergit represents the last, 
chitinized remainder of the 10th segment. In this way the 10th segment does not only differ almost invariably 
from one species to the other in the Trosiinae , but it shows in distinctly separable groups of species an ever 
varying organization which is determined by the absence or presence, by the separation or anastomosis, finally 
by the dorsal, lateral, or ventral position of its constituents: uncus, socii, and gnathos. Thus the stages of deve¬ 
lopment of the 10th segment contrast with each other, explicable as a checking and, at the same time, as a 
specialization of its development. These stages were assumed for the Trosiinae as the foundation for deter¬ 
mining the genera. If we compare the Megalopyginae and Aidinae with this generic principle we notice that, 
in these two divisions, the organization of the 10th ventral segment has almost been stationary at a certain stage 
of development. Their genera and partly also their species are not equivalent to those of the Trosiinae. 
I. Trosiinae. 
Excepting the mostly brightly marked and coloured species of Mesoscia and Trosia, we are chiefly met 
with a want of marking and with white colouring among the Trosiinae to which also the pygmean Megalopygidae 
belong. The few species that are coloured or provided with a scheme of markings on the wings generally take 
up an archaic position within their genus according to the state of the 10th ventral segment, and we may con¬ 
clude from this that their scanty, uncomplicated and variable colouring and marking is rudimentary and that 
the many purely white species have issued from marked and coloured primary forms. By the loss of pigments 
a convergency of the species and even of the genera in their outward appearance has been produced, as is un¬ 
equalled in the lepidopteral kingdom. We may only remember species such as Alesoscia itatiayae, Macara pasa- 
leuca, and Norape beggoides, wiiicli can easily be confounded, if their generic character is not ascertained from 
the 10th segment. The white unmarked species of Norape , numbering far more than 40, are almost exclusively 
determinable by the very constant and heterogeneous shape of their male sexual armature. Yet it is absolu¬ 
tely necessary for determining the genera to examine first of all the 10th ventral segment of the AS- If this 
is neglected, only few genera remain that are discernible by their different neuration, and these may be placed 
ahead of the others. 
A. Less than 11 veins from the cell o f t h e f o r e w i n g. 
1. Genus: Zyzypyge Hopp. 
Only 9 veins or vein-branches respectively proceed from the cell of the forewing, the 3rd and 5th radial 
branches are absent. The only species hitherto known exhibits almost plain, flattened antennae of the A in 
contrast with all the Megalopygidae. The 10th abdominal segment shows a tergit-appendage (uncus) in the 
shape of a roundish, bare plate from the centre of which a plain, slightly curved thorn arises. The genus appears 
to be highly specialized owing to these characteristics. The only species is: 
V. calycina Hopp (160a). Thinly scaled, semidiaphanous, faintly marked by dark brown and white calycina. 
scales. Head, thorax, anal aperture, and legs white-haired, hindlegs blackish above, abdomen black, loosely 
covered with white hairs. Antennae light brownish, scantily scaled white. Expanse of wings: A mm. 
Taperinha, Amazons. 
2. Genus: Vescoa Dyar. 
Only 10 veins proceed from the cell of the forewing, the 3rd radial branch is absent. Distinguished 
from two other genera that are characterized in the same way by the 1st radial branch of the forewing not 
extending separately, but in a long anastomosis with the subcostal vein. The 10th segment is similar to that 
of Malmella, the not paired uncus borders dorsally, as a bare ridge ending in a small thorn, on the entirely fused 
socii which are provided with a structure of tactile hollows. Only one species: 
VI 
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