( cxiv ) 



Mr. Charles William Dale died in February last at the 

 age of fifty-four, at Glanville's Wootton Manor House, Sher- 

 borne, where most of his life was passed. Among other works 

 he wrote "The History of Glanville's Wootton, including its 

 Zoology and Botany" (1878), "The Lepidoptera of Dorset- 

 shire " (1886), with a second edition (1891). The fine collection 

 of British insects made by his father, James C. Dale, passed 

 to him, and, with many additions made by himself, was 

 bequeathed to the Hope Mviseum at Oxford, where it arrived 

 last summer. 



A very eminent foreign entomologist, one of our Honorary 

 Fellows, Baron C. R. v. d. Osten-Sacken, died at Heidelberg 

 in May last, aged seventy-eight. The first of his writings, on 

 the Tipulidje, published in 1854, showed the attraction which 

 the Diptera had for him, and this was the Order of insects 

 to which the principal part of his entomological work was 

 devoted. But he was distinguished in many other ways. 

 Twenty-one years of his life were spent as Secretary to the 

 Russian Legation at Washington, and he presented his great 

 American collection to the Museum of Comparative Zoology 

 at Cambridge, Massachusetts. Knowledge of the Diptera 

 was greatly advanced by his numerous contributions. His 

 wide accompli.shments and engaging personality added deep 

 regret to the sense of the loss sustained by science in his death. 



I proceed to the subject of my addi^ess. 



I propose this evening to inquire into some of the causes of 

 the persistent abundance or scarcity, generally and locally, of 

 species and varieties of insects, and the relative importance, in 

 this connexion, of their consumption of food and the attacks 

 of their enemies. I shall have to refer to the large number of 

 striking characters that appear to be of no biological import- 

 ance ; to the desirability also of observing and recording habits 

 and activities — including those not directly concerned with 

 nutrition or reproduction — not disregarding the psychical 

 element which controls and guides action in these highly- 

 organised animals. I propose also to call attention to the 

 manner in which their activities and the motive-springs of 

 them are affected by external conditions, and to the structure 



