SPOLIA ZEYLANICA 
THE PLUME-MOTHS OF CEYLON 
Part I—The Pteropharidse. 
By T. Bainbrigge Fletcher, R.N., F.E.S. 
(With 5 Plates and a Map.) 
Introductory. 
I N popular language the term “ Plume Moths ” generally 
includes the members of two families, the Pterophoridse or 
true plumes and the Orneodidse or 24-plumes, whose common 
peculiarity lies in the fact that their wings are more or less 
split into segments resembling feathers or plumes. Both these 
families are doubtless very ancient forms, as is shown by their 
universal distribution and the absence of any other nearly allied 
groups. Nor must it be imagined that the Pterophoridse and 
Orneodidse are at all closely related, merely because they are both 
included under the popular term of “ Plume Moths ” ; as a matter of 
fact, they seem as little related to one another as either is to any 
other group of the Micro-lepidoptera. 
Fission of the wings, indeed, occurs sporadically in many other 
groups of the Lepidoptera : for example, the Syntomidse (which 
have been held to be the most specialized of all moths) include the 
curious Trichceta pterophorina , Mab., from Natal and Mashonaland, 
in which the fore wing is deeply cleft; the Arctiadae include Ehago- 
phanes tortriciformis, Z.,from Java, in which the hind wing is cleft 
to its middle ; whilst amongst the Oxychirotidae we find Cenoloba 
obliteralis, Wlk. (specimens of which I possess from Trincomalee), in 
which both wings are cleft into two segments. 
As regards any advantages conferred by this fission of the wings 
nothing is known, but it seems probable that some advantage will be 
found in considering the mechanics of flight amongst these species. 
Where rapidity of flight is not a desideratum it appears reasonable 
to suppose that a light framework of wing (so to speak), supple¬ 
mented by a large surface of long cilia, will be of advantage as 
compared with the ordinary type of lepidopterous wing by giving 
an equal measure of aerial support for less weight, and consequently 
less expenditure of muscular energy ; the same device is seen in 
7(6)09 
B 
