442 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1926 
distinct odors in various other types, the names of which he did not 
know. 
In a male of Tarucus theophrastus from the Sudan Mr. Longstaff 
found a moderately strong, sweet, luscious scent. 
All of the remaining records are from Ceylon, where they were 
gathered by Mr. Longstaff. Two males of Nacaduba atrata had a 
sweet, flowery scent, confirmed by Mrs. Longstaff and in one case 
compared by her to “ very, very faint jasmine.” Five males of ZLam- 
pides elpis, all of those examined, had a sweet scent which in one 
was with some hesitation compared to clover. Nine males of LZ. lacteata 
all had a distinct odor which was compared to vanilla biscuits or to 
chocolate candy. These two closely allied species therefore have 
quite different scents. A minority of the numerous males of Z. celena 
which were examined had a faint, sweet scent. About half of the 
males of Polyommatus beticus had a slight scent like that of meadow- 
sweet. ‘Three males of Rapala lazulina yielded a scent like that of 
vanilla biscuits. 
Skippers.—Among the skippers, or Hesperide, which are mostly 
very small, there are but few observations, though in very many scent 
scales are extraordinarily developed in various places on the wings 
and even on the tibiw of the hindmost legs. 
In Plestoneura eligius and in a species of Achlyodes from Brazil 
Fritz Miller noticed that the pencil of long hairs on the hindmost 
tibize of the males emitted a very faint odor. In the South African 
Gegenes occulta Doctor Dixey found a very distinct chocolate scent 
in a male. 
FUNCTION OF THE ODORS 
What is the purpose of the fragrance of the males of butterflies ? 
Last summer I watched the courting process in Argynnis cybele. 
A female was seated on the upper surface of a horizontal leaf with 
the wings folded tight together and the fore wings drawn back- 
ward to the maximum, a somewhat unusual and strained position for 
this insect when sitting on a leaf, but one which was maintained 
unchanged throughout the whole performance. An inch or so be- 
hind the female on the same leaf was a male, his body just in line 
with hers and facing the same way. His wings were close together, 
but the fore wings were drawn far forward so that their hinder 
border approached the vertical, as that of hers did the horizontal. 
At intervals he would suddenly open and close his wings, these 
intervals, at first about a second, becoming less and less; and con- 
stantly, almost incessantly, he slightly shifted his position, in a 
series of little rapid jerks. 
The same drawing forward of the fore wings of the male, the 
spasmodic opening and closing of the wings, and the constant 
