hind end was meant to look 
like a head. Is it so per- 
haps, that this species has 
the habit of moving its wings 
up and down in other (more 
southern ?) countries but has 
lost the" habit here, or does 
Fig. 19. keel ae Urd ned hg Th. W- it do <£0 only now and then 
everywhere? This would 
further lead to the question, whether it is a form representing only 
an incipient stage of this habit and character, or it is perhaps a 
reduced stage, where this habit is about to be lost. It seems to me 
that a more close study of this and allied species might perhaps 
give the solution of the interesting question, how" this remarkable 
character has developed. The fact, that the Lycæna's or ,Blue's" 
generally have the habit of moving their hind wings up and down 
must be of considerable importance in this connection. It may prob- 
ably be the starting point of the evolution of this character. AS 
I have no special knowledge of Lepidoptera I can only give these 
suggestions and direct the attention of specialists to this highly 
interesting problem. 
Pieper's (Mimicry etc., 1903. p. 434) in accordance with his 
theory of the reduction of the wings in insects, asserts that the 
appendages of the hindwings in Lycænids are ,nichts anders als 
die letzten Relikte von einer friiheren gråsseren Ausdehnung der 
Fligel, welche in dem evolutionellen Prozess der Verkleinerung 
auf dem Punkt stehen um ganz zu verschwinden ..... Offenbar 
muss dann die Form dieses Schmetterlinges, bei der jene Schwånz- 
chen am meisten fehlen, auch diejenige sein, welche am weitesten 
evolutioniert ist". I am not competent to judge of the correctness 
of Piepers' theory of the wing reduction, and the — thus far 
quite logical — conclusion that those species with the smaller ap- 
pendages are the more reduced. But that these appendages are 
nothing but the last vestiges of the greater extension -of the wingS 
is, evidently, not correct; their very large size in some species, (in 
Sithon tharis Hibn. e. g. they are as long as the distance from 
the tip of the forewing to the end of the hindwing), the often 
white, slightly enlarged tip (— representing the thickened end of 
