28 proceedings: biological society 



extreme degree. The change in the composition of the vegetation 

 with the increase in altitude has been dwelt upon by several travellers 

 and botanical explorers of the Isthmus; it is very gradual but never- 

 theless very radical. Several genera of trees observed at high alti- 

 tudes are gregarious; there are, for instance, oak-forests, sub-tropical 

 or even temperate in their general appearance. Lantern slides illus- 

 trating types of forest, or of individual trees and flowers, were shown 

 at the conclusion of the lecture. 



J. H. Paine : Scientific photography in the study of insects (Illustrated 

 by lantern slides). 



M. W. Lyon, Jr., Recording Secretary. 



