TRANSACTIONS OF SECTION D. 401 
13. Report on the Inheritance and Development of Secondary Sexual 
Characters in Birds. 
14. Report on Zoology Organisation. 
15. Report on the Formulation of a Definite System on which 
Collectors should record their Captures. 
16. Report on a Natural History Survey of the Isle of Man. 
WEDNESDAY, AUGUST 19. 
The following Papers were read :— 
1. On Scent-Distributing Apparatus in the Lepidoptera. 
By F. A, Drxty, M.D., F.RB.S. 
Tt is well known that certain specialised scales found in various situations 
on the wings, bodies, and limbs of Lepidoptera are concerned in the distribution 
of a scent, which in many cases is characteristic of the species. These scales 
may occur in both sexes, but certain forms of them have only been found in 
males; among these are the plume-scales of the Pierines and Nymphalines. 
The Pierine plume-scale often affords a ready means of identifying the species, 
and is frequently of service in throwing light on questions of affinity. Thus, 
the interesting butterfly Zeuciacria acuta Roths. and Jord., recently discovered 
in New Guinea, has been considered by some authorities to be nearly akin to 
the African genus Pinacopteryx, and by others to the Australasian genus 
ELlodina. But the scent-scales with which it is abundantly furnished bear no 
resentblance to those of any Pinacopteryx, while Hlodina appears to be entirely 
devoid of these structures. On the other hand, the scent-scales of Leuwciacria 
strongly recall those of Delias, a genus well represented in the Australian 
Province, and especially so in New Guinea. Scales of a somewhat similar 
character are also found in Huphina, another genus with an Oriental and Aus- 
tralasian distribution, and probably not far removed from Delias in point of 
affinity. In a further structural feature Zeuciacria is nearer to Huphina than it 
is to Delias, and it may possibly turn out to be a connecting link between these 
two assemblages. But from the evidence of the scent-scales it seems safe to 
conclude that such resemblance as exists to Pinacopteryx and Mlodina is only 
superficial. The well-known ‘battledore scales’ that occur on the wings of 
Lycenids furnish a means of separating two species, Plebeius cegon and P. 
argyrognomon, which are often indistinguishable by ordinary methods of 
examination. 
In some cases, though not in all, a special adaptation exists with the object 
of economising the scent until it is required for purposes of sexual recognition 
or attraction. The costal folds of the forewing in many Hesperids, noticed by 
Doubleday and Westwood, and first adequately described by Fritz Miller, are 
examples of this kind of provision. Another structural feature serving the 
same purpose is the collection of the scent-distributing scales into a patch on 
that portion of the fore or hind wing which is covered in the position of rest. 
This arrangement is seen in many Pierines; it occurs also in Satyrines and 
Nymphalines. No example of a male characterised by special scent-scales was 
known to Fritz Miiller among the Erycinids. Such, however, do exist; as, for 
example, in the genera Mesosemia and Pandemos, where the scent-patches 
occlude one another in the attitude of rest, as notably in the genus Dismorphia 
1914, pD 
