president's address. 
149 
LESSONS TO BE LEARNT FROM A LARGE 
COLLECTION OF BUTTERFLIES. 
In selecting a subject for a Presidential Address, I have 
had much difficulty ; but on looking over the large collection 
of Butterflies which I have formed, it struck me that some 
interesting facts ought to be derived from the study of 
this material. I was reminded by a remark made by an old 
naturalist, Burchell, who travelled in South Africa in 1810-15, 
and afterwards in South America, and who made large 
collections. He says : “ To him who is satisfied with the 
amassing collections o'f curious objects, simply for the pleasure 
of possessing them, such objects can afford at best but a 
childish gratification, faint and fleeting ; while he who extends 
his views beyond the narrow field of nomenclature, beholds 
a boundless expanse, the exploring of which is worthy of the 
philosopher, and of the best talents of a reasonable being.” 
Now on reviewing a large collection of Butterflies, one is 
naturally struck with the lessons connected with the dis- 
tribution of animals over the surface of the globe which 
they teach us. Lepidoptera through the quality of flight 
partake of the powers of dispersal possessed by birds ; 
consequently there are some which may be termed cos- 
mopolitan. Herr Gaetke, of Heligoland, a former member 
of this Society, gives an interesting account of the migration 
of Plusia gamma, a well known British Moth. He 
states that on the night from i5-i6th of August, 1882, from 
11 p.m. to 3 a.m., millions of P. gamma were travelling 
from east to west like a dense snow storm. Again, on the 
nights of the 16th, 17th, and 18th, large numbers of P. gamma 
passed the island, the migrations commencing each evening 
at eleven o’clock. On the 19th the wind was south-east, 
the weather fine and calm. In the evening the sky became 
overcast, and a strong migration of birds took place. 
From 11 p.m. till 2 a.m. thousands of P. gamma were again 
