I. HAIR-TUFTS, ETC., OF MALE LEPIDOPTERA 613 
occasion, either in the male of orcus or of any other Hesperid, and I could 
not understand how by pinching the thorax I had brought about the 
unfolding. Probably it had been already accomplished by the ardent 
male himself. 
From the very first I never expected to find in all the above-mentioned 
species any striking scent, or indeed one that would be perceptible to the 
human nasal organ. Our sense of smell is very imperfectly developed, 
even in comparison with many mammals, and its inferiority may be 
far more pronounced when compared with certain insects, especially 
Lepidoptera. It is well known that the females of Moths attract the 
males from almost incredible distances ; and the certainty with which 
butterflies are able to discover the food-plants of their larvae, suffices to 
prove the keenness of their scent. Thus, to the female butterfly a scent 
which is not perceptible to the human nose, may appear quite strong. I 
was, therefore, not surprised at being unable to detect any scent from the 
brands of several species of Thecla , or from the large, mane-covered 
chalky patch of Callidryas trite, 1 and I do not find in this inability any 
objection to my explanation as to the purpose of such structures. 
I may be permitted to take this opportunity of also mentioning some 
other scent-distributing organs of diurnal Lepidoptera. 
The males of most species of Glaucopidae are able to protrude two long 
hollow tubes from the apex of the abdomen. Sometimes (Leucopsumis sp.) 
these tubes are longer than the body, and on protrusion curl up like rams’ 
horns. They are as a rule beset with hairs, which are erected in the act 
of protrusion, and they usually give off a more or less powerful, and to us 
unpleasant, smell: especially strong, and in this case not unpleasant, is the 
scent of the magnificent Belemnia inaurata (Euchromia eryx ), recalling at 
the same time prussic acid and chloroform. Entirely similar, strong 
smelling tubes I found in a moth, the name of which I do not know. 2 3 
With all their external differences, these tubes of the male Glaucopidae 
are adapted to fulfil the two requirements of a scent-distributer which we 
noted in the butterflies :—protection against unnecessary evaporation, and 
the exposure of a large surface, when the scent is to be emitted. 
It is worth noting that within the group of the Ithomiinae and their 
allies, both these structures occur, and appear to represent each other. In 
Lycorea 3 the tuft on the anterior margin of the hind-wing, which occurs 
in most of the Ithomiine genera, is wanting ; but then the males possess 
1 See terminal note, p. 615. 
2 Identified by Dr. Staudinger as a species of Cryptolechia. —F.M. [Tbe classifica¬ 
tion and synonymy of the moths referred to in the above paragraph have been entirely 
changed since the date at which this memoir was written. Glaucopis = Syntomis. 
Leucopsumis is a Hypsid, Belemnia an Arctiid, Euchromia a Syntomid. See also 
Nature (1874), p. 102, for a letter dealing with the Glaucopidae , written April 20 
[1874], by F. Muller to Charles Darwin.—E.B.P.] 
3 See note 1 on p. 605. 
