292 Dr. Frederick A. Dixey on the 
hindwing, and in the latter situation the discoidal spot 
has at this stage scarcely become recognizable ; in some 
species, however, a patch of pale-coloured scales covers 
the lower disco-cellular nervule of the hindwing in the 
midst of a wide and not sharply-defined area of dark 
ground colour. 
So far little or no essential difference has been noted 
from the primitive pattern of Hucheira socialis; the 
variations produced having simply resulted from a 
greater or less extension of the intrusive pale tint along 
the lines originally marked out. But, on turning to the 
underside of any species of Catasticta, we find what at 
first sight appears to be a very considerable divergence. 
A careful examination, however, soon makes it plain 
that the pattern of the lower surface is throughout the 
genus essentially the same as that of the upper surface, 
though one or two new features are superadded. Con- 
fining our attention in the first place to the forewing, 
for instance in C. nimbice, we find the submarginal series 
S and the discoidal spot shown at least as clearly as on 
the upper side; while from the greater prominence of 
the pale spots at the extreme margin, M is brought still 
more plainly into view below than it is above. On the 
hindwing, the central pale band may be easily traced 
across the disc of the wing, leaving on the one side of it 
a basal, and on the other a broad marginal dark area. 
Traversing the latter can be seen a row of elongated, 
more or less wedge-shaped, yellow streaks, which repre- 
sent the more easily recognized series I of the forewing ; 
while a distinct row of yellow spots on the extreme 
margin continues the similar series from above. Though 
S and M are not yet sharply marked off from one 
another, the portions of dark ground colour to which 
they respectively belong are already separately recog- 
nizable. The undersides of C. nimbice, C. colla, C. toca, 
and C. corcyra will be found to make a very good 
transitional series, showing the gradual emergence of 5 
and M and the subsequent reduction of each to a mere 
festooned line.* The superadded features above alluded 
* An unnamed species of Catasticta in the British Museum 
presents a condition of the underside of the hindwing more exactly 
intermediate between C. corcyra and the usual type than any of 
the species mentioned. An individual of the same species is in 
