DREPANIDAE. General Topics. By Dr. A. Seitz. 
443 
12. Family: Drepanidae. 
This family containing about 3 to 400 forms is often ranged by the name of Platypterygidae owing 
to the derivation from one of its most poly typical genera, Platypteryx Lasp. A third family name, Drepa- 
nulidae, however, is used without authorisation (Kirby), for there is no generic name of ,,Drepanula“ in this 
family, but it exists in a family of butterflies (cf. Vol. V, p. 698, pi. 133 e, f). Schranck denominated that 
genus ,,Drepana“. 
About 80 per cent, of the species belonging to this family exhibit a remarkable consistency in the 
shape of the wings (falciform fore wings) as well as in the colouring (varying from yellow to brown) and even 
marking (oblique line in the distal portion of the fore wing, and the cell-end spot). Most of the species are also 
of less than the medium size of the Heterocera, showing an expanse of wings of 2 to 4 cm, so that the occur¬ 
rence of silvery scales and some conspicuous indentations in the margins of the wings are the only extrava¬ 
gances noticeable. 
The systematic position must be regarded as provisional up to this day. The Geometrid-like habitus, 
which is also laid stress upon by Warren in the following pages, has already been commented upon in Vol. II 
(Strand p. 195), although the resemblance is always stated to be merely quite external. Hampson and Stau- 
dinger-Rebel have placed the family directly before the Callidulidae, and the latter authors (as well as Kirby) 
range it after the Bombyculae , from which Hampson separates it rather distantly. Packard considers it to 
be an offspring of the Notodontid tribe (and the Bombyculae, to be another offspring); he was probably in¬ 
fluenced by regarding the very much specialised larvae of the Drepana. — Certain relations to the Thyridi- 
dae have been commented upon in Vol. II to which we also refer (p. 195) with respect to the principal marks. 
The range of the family is rather irregular, since it has a most remarkable centre in British India. 
They decidedly require great dampness in summer combined with great heat, and both Africa and Australia 
exhibit vast districts where the family is entirely absent or where hardly one isolated species represents it; 
above all they hardly occur at all in the deserts, and in the oases of the Sahara only 2 species are met with. 
Their main range in the Old World extends from the torrid parts of India, particularly the Himalayan coun¬ 
tries through Assam to South China and Japan on the one hand, and across the Malay Archipelago to New 
Guinea on the other hand. Europe as well as North America only contain 7 or 8 species, the Ivhasia Hills 
boast of numerous though rather closely allied forms. In Tropical America they are almost quite absent, but 
they are replaced there most conspicuously by a certainly allied lepidopteral tribe — the Perophoridae - 
which is even included in the family by some systematisers, although its larvae are quite differently specialised. 
These Perophoridae are represented in Tropical America by about 100 species; about 1 to 2 dozens of species 
occur in every larger geographical district, so that about the same proportion prevails there as in the Indian 
faunal regian regarding the range of the Drepanidae. 
As to the distribution within the Indo-Australian Region most of the districts contain at least about 
a dozen species, except Australia where, as we mentioned above, they occur very rarely. Arabia, the eastern 
coast of which only belongs to our fauna (its northern part being palearctic and the southern part Ethiopian), 
hardly possesses one species, but on the opposite coast of India quite a number of species occur already, 
and in the Nilgiri Mts., where Hampson ascertained 12 species, I found single forms rather frequently. Ceylon 
has 9 species, some in common with Southern India. From there to Bengal and Assam their number increases 
rapidly, attaining its maximum in the Khasia, Naga, and S ikki m Mts.; from some of these districts up to 
50 species are known, most of which we figure here for the first time. From here to the south and east their 
number decreases again, but there still occur more than about 20, where the palearctic southern frontier shuts 
off the faunal region, in Southern China and the southern most parts of Japan. From the Philippines which, 
however, are still very insufficiently explored, Semper only enumerated three species. 
We cannot say that the Tropical-Indian Drepanidae excel the eastern palearctic species to a conside¬ 
rable extent. On the contrary, we know the Cyclidia (Euchera ) of North China and Tibet, the Auzata and Ma- 
crauzata of Japan to be the most eminent palearctic forms, whereas the Indian Fauna contains mostly poly- 
typical genera looking almost like insignificant European species such as Drepana curvatula or cultraria. 
