156 Mr. R. Meldola on Evolution. 
Display of Colour by Lepidoptera. 
With reference to the display of colour by butterflies and 
moths, Mr. Darwin has already * recorded the case of a 
species of Castnéa which possesses ornamented hind wings 
and displays them, while other species with plain hind wings 
do not display them +. Fritz Miiller adds the followmg in- 
teresting case :—‘‘ I observed a curious little fact with our 
Hesperide. Most of them are of a dull brownish colour ; but 
there are some in which the wings have a more or less vivid 
blue tint either on the upper or on the lower surface. Now the 
former when alighting on a flower always hold their wings 
expanded in a horizontal plane, while those of the latter are 
folded vertically, so that in either case the blue surface is 
exposed to view.”” Without further observation it cannot be 
assumed in this case that the colour is displayed as a sexual 
attraction, since it is well known that colour is displayed for 
other purposes, such as for protection, when the colour is a 
signal of distastefulness (as with brightly coloured larve, and 
those species which serve as models for mimicry), or for 
giving resemblance to some coloured objects, such as flowers. 
Insects distinguishing Colours. 
The distinguishing of colours by insects has been proved in 
the case of bees and wasps by Sir John Lubbock’s experi- 
ments. This faculty is of paramount importance to the theory 
of sexual selection}. Fntz Miiller states, ‘ Butterflies not 
only discover flowers by colour, but certain species even give 
an unmistakable preference to certain colours. Thus Calli- 
dryas Philea and some other species of that genus almost 
exclusively visit brilliant red flowers (Canna, Salvia). Ared 
Hedychium in my garden was constantly surrounded by a 
multitude of Callidryas Philea (and of Papilio Thoas) ; and so 
are at present some other plants with red flowers, while they 
never alight on plants of the same and other genera with yellow, 
white, or blue flowers.” 
Mimicry. 
It has hitherto been considered a general rule that a 
mimicked species is commoner than the species which mimics 
* Descent of Man, 2nd ed. p. 314. 
+ Ibid. 2nd ed. p. 315. Mr. Darwin has called my attention to Fritz 
Miiller’s “ Beobachtungen an brasilianischen Schmetterlingen,” a paper 
which contains some further remarks bearing on the subject of display, in 
the October number of ‘ Kosmos.’ 
{ ‘Descent of Man,’ 2nd ed. p. 317. On the attraction of Macroglossa 
stellatarum by colour, see a letter in ‘Nature,’ vol. xvii. p. 11, Nov. 1, 
1877. 
