
LEPIDOPTERA IN RELATION TO FLOWERS. 355 
from that of the more common Orchestia littorea, being some-. 
what pear-shaped, broad at the base, while a strong claw 
springs from the narrow apex; and the palm is furnished with a 
distinct tooth near the base of the claw. 
Isopopa. 
All the Isopods mentioned in the list have already been 
recorded for the Clyde area; they are all included in Dr. 
Robertson’s Catalogue of the Amphipoda and Isopoda of the Furth 
of Clyde, published by this Society a few years ago. 

The Lepidoptera in relation to Flowers. 
By Grorcr W. Orp. 
[Read 28th March, 1899.] 
NowzereE in the annals of Darwinism has a battle raged more 
fiercely, than in regard to that application of the theory of natural 
selection which deals with the relationship between plants and 
insects. No doubt the insect selection theory, in that it has 
encouraged research, has done great good, and there can be 
equally little doubt that it has a broad basis of truth. That 
cross-pollination is necessary for many plants, and desirable 
for all, no botanist doubts. Further, that the agency of insects 
is in many cases absolutely essential for such cross-pollination is 
also indisputable ; and when we find that in many such cases the 
form of the flower and the arrangement of its parts are such as to 
make fertilisation by visiting insects a certainty, we are fully 
justified in believing that that form and that arrangement must 
in some way be connected with the long continuance of such 
visits. 
The theory stated so broadly is practically unassailable, but 
it was not necessary to try to prove that every freak of plant 
nature, every line and every shade of colour, was thus brought 
about. Yet this is exactly what has been attempted. Sir John 
