EHOPALOCEEA. 
27 
is at rest) is more or less protective, from its obscurity or its resem- 
blance to the tints of the customary surroundings. 
In two genera of butterflies, viz., Acrcea of the Sub-Family Acrocince, 
and Farnassius of the Sub-Family Papilionince — which are very remote 
from each other in almost every respect except their semi-transparent 
wings — the females exhibit a very remarkable and quite peculiar 
structure, in the form of a horny pouch or sac, attached to the under 
side of the abdomen. In Acrcca this appendage is on the penultimate 
segment, and is of moderate size, being best developed in A. Neobule 
and A. Horta ; but in Parnassius it is much larger, and in P. Delius 
is widely open posteriorly, and occupies the whole under side of the 
abdomen. The use of this pouch — which is often detached and lost 
during life — has not been satisfactorily determined. 
A curious difference between the sexes is presented in several genera 
of Lycmnidce^ — such as Umnceus, Myrina, Deudorix, and Capys^ — where 
the palpi of the female are considerably longer than those of the male. 
The same character is noted by Westwood (in G-en. Diurn. Lep^ as 
occurring in three genera of Erydnidm^ viz., Alesia, Nymphidium^ and 
Aficoris. 
It occasionally happens that the male and female characters are 
combined in one and the same individual butterfly, and, where the 
secondary sexual differences are very marked, the appearance of such 
an example is very singular. Boisduval {Sp. Gen. Lep.^ i. p. 27) men- 
tions eight species of which so-called " hermaphrodite " individuals had 
been noticed by authors, and a good many other cases have been re- 
corded. A recent instance in South Africa is that of a specimen of Lycmna 
Telicanus (Var. pulchra^ Murray), taken near Grahamstown by Mr. F. 
Billinghurst, in which the wings of the right side are of the female 
pattern and colouring, while the left-hand wings are of those of the male. 
5. Haunts and Habits. 
The dependence of Butterflies on vegetation (especially in their 
caterpillar state), and their need of shelter from high winds, explain 
how it is that they chiefly abound in wooded districts. Sunshine, a 
still atmosphere, and flowers are the surroundings most favourable to 
the great majority of them : in exposed spots, when the weather is 
boisterous, nearly all species are helplessly driven before the gale, and 
they speedily succumb to combined cold and rain. There exists, of 
course, a large number of species found in open country, and many are 
peculiar to such tracts (especially in mountain stations), but forest-clad 
lands are incomparably richer. Only a few butterflies, however, inhabit 
the depths of woods, the great gathering of them being on the out- 
skirts, or where the forest is broken by open spots and the sunshine 
has access. In South Africa, the richest collecting-ground is the 
wooded coast of Kaffraria, Natal, and Zululand, and the country about 
Delagoa Bay seems almost equally productive* 
