11 



Many of these will be of great value in the Mimicry Col- 

 lection. 



A large collection, presented by Herbert Druce, Esq., F.L.S., 

 consisting of butterflies from Africa and South America, and 

 moths from Central America. These will be of great value 

 to the general collections. 



Dr. Dixey's important present of British Insects from the 

 neighbourhood of Morthoe, N. Devon, is also at present 

 uncatalogued. 



Additions to the Collection in 1898. 



The great strain thrown upon the Department by the acces- 

 sions in 1897 has only permitted a small proportion of the 

 specimens presented in ICS98 to be as yet catalogued. 



One of the most interesting additions made in recent years 

 to the Department and the Museum is due to the kindness of 

 Abbott H. Thayer, Esq., of Scarborough, N.Y., U.S.A., who 

 prepared and painted models of two birds, illustrating the 

 reason for the gradation of the colours of animals in nature 

 — from dark on the back, through lighter shades, to white 

 on the belly. These models show the difference between 

 a uniform tint and colours so graded. In the latter case 

 the increasing lightness is seen exactly to neutralize the 

 increasing shade as the sides and under-surface of the animal 

 are more and more shielded from the light of the sky in 

 passing from the back to the belly. Furthermore the cold 

 white light of the sky combined with the brown of the 

 animal's back produces a colour-effect similar to that of the 

 brown reflection from the earth combined with the cold white of 

 its under-surface. The uniformly coloured model stands out in 

 startling contrast beside the graded one which is inconspicuous 

 and almost ghost-like, as so many animals are in nature. 



The nest of a Marsh Warbler [Aa^ocephaliis palustris) from 

 Kingham, containing a cuckoo's egg buried under the lining, 

 was presented by W. Warde Fowler, Esq., M.A. (Lincoln 

 College). A nest of the Long-tailed Tit [Parns cmidatus) 

 was presented by G. Holding, Esq., M.A. (All Souls College). 

 A nest of the Great Reed Warbler {Acroccphalus turdoidcs), 



