LEPIDOPTERA IN RELATION TO FLOWERS. 355 



from that of the more common Orchestia littoi'ea, 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. 



ISOPODA. 



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 Ami^hipocla and Isopoda of the Firth 

 of Clyde, published by this Society a few years ago. 



The Lepidoptera in relation to Flowers. 



By George W. Ord. 



[Read 28th March, 1899.] 



Nowhere 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 tr}'- 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 



