Miarvels of the Universe 93! 
although they vary in different species, in some cases being quite hair-lke. They are situated on 
various parts of the wings, sometimes along the veins, but more often in bands and patches in 
particular areas, according to the species. They are believed to be associated with scent-glands 
contained in the wing structure, and on that account become very interesting objects. 
We have already observed that butterflies and 
moths carry on sensory functions which are diff- 
cult to understand when measured from the human 
standpoint. It is, therefore, extremely interesting 
to find that the male butterfly, when love-making, 
resorts to human methods, so far as to make 
himself attractive with perfumes that are quite 
familiar to our own sense of smell. 
It is still more interesting to find that each 
species of butterfly has its characteristic odour. 
For example, the familiar Small White Butterfly 
of the garden favours sweetbriar or ripe-apple 
perfume ; while its near relative, the Large White 
Butterfly, delicately puffs the air with a scent some- 
what like violet-powder. Another near relation, 
the Orange-tip Butterfly, fascinates his spouse with 
a fairly strong smell of lemon ; indeed, the scents of 
the different species are as varied as those of the 
flowers which supply them with liquid food. 
The female insects also appear to emit similar 
odours, but it isin the males that they are most 
perceptible. If the wings of a freshly-captured 
male butterfly are gently rubbed, so as to remove 
some of the surface scales, its characteristic per- 
fume may sometimes be readily detected. They 
appear, however, to be able to control the emission 
of these odours, and a specimen which has been 
exercising its wings may not prove so_ strong- 
smelling as one which has just commenced flight 
in the morning sunlight. Possibly the fluttering 
and circling movements around each other seen 
when these insects are flying are owing to the male 
insect’s endeavours to get on the wind-side of his 
mate, or that he may get into a favourable position 
to fan his perfumes towards her. 
It is possible that some butterflies may favour 
scents similar to the flowers which they most 
frequent when in search of food. In that case, it 
would be of material advantage to them both in 
attracting and in finding their mates, as their sense 
of smell for their choice food-plants would neces- 
sarily be highly developed. That, however, is a 
Photo by] [E#. Step, F.LS. 
THE PEA CRAB. 
This is one of the smallest of Crabs, and is an in- 
timate associate of the mussels, in whose shells it lives. 
Here are shown: topmost, the male; below the female, and 
lastly the female with the large tail-plates disclosed, for 
these are usually folded up and packed away under the 
shell. 
point which, so far as I know, has not been investigated. 
In any case, these curious scent-glands only present another instance of what marvels of nature 
may be hidden away, even amongst the extremely minute scales which clothe a butterfly’s wing. 
