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§ III. On the Scent-organs of the Butterflies , Epicalia 
acontius, Linn., and Myscelia orsis, Drury . 1 
Plate B. 
The [Nymphaline] genus Epicalia, Westw. (or Catonephele, Hiibn.), has 
acquired a certain celebrity (Darwin, Descent of Man , 1871, vol. i. p. 388) 
from the extraordinary difference in colour exhibited by the two sexes in 
many of its species. Thus, if we compare Epicalia numilia, Cram, with 
E. acontius , L., we see that the females of the two species, and in like 
manner the males, resemble each other far more closely than do the females 
their respective males. The males of both these species are ornamented 
with large and splendid orange markings on a ground of black velvet. E. 
numilia has three separate elliptical spots (two on the fore-wing and one 
on the hind), while E. acontius {gntiochus, Fab.) has one such spot on 
the fore-wing, uniting with one on the hind to form a band crossing both 
wings. In the females the wing spots are of a sulphur yellow and of an 
entirely different shape from those in the opposite sex : in E. acontius 
(medea , Fab.) they are very numerous and are arranged in three parallel 
lines. In fact, the differences between the two sexes are so great, that 
Westwood placed them in different genera, giving the name of Myscelia 
medea to the female of Epicalia acontius. 
The two species which I have just mentioned—the only Epicalias as 
yet met with in the province of Santa Catharina, are most interesting, 
inasmuch as the males, which are otherwise very similar, exhibit the most 
remarkable differences in respect to their scent-organs. In the males of 
E. numilia I have not found it possible to detect the slightest vestige of 
such organs, and they appear to be entirely wanting in these insects. In 
the males of E. acontius , on the contrary, they attain a somewhat unusual 
degree of development, and exhale a very strong odour. These scent- 
organs are hidden between the fore and hind-wings, occupying the upper 
surface in the latter, the lower in the former. On the hind-wings there 
is seen (PL B, Fig. 11), close to the orange spot ( b ) a still larger patch 
of grey colour ( m ), which lacks the velvety appearance of the rest of the 
wing, and may rather be compared to a kind of felt. This felted patch 
(“ Filzfleck,” Herrich-Schaeffer) is bounded by the dorsal [costal] (8) and 
1 Archivos do Museu National do Bio de Janeiro , II. (1877), pp. 81-35. By Dr. 
Fritz Muller, Travelling Naturalist for tire National Museum. 
