641 
1921 .] the Near East and Tropical East Africa. 
Galerida theklse Brehm. 
At Solium I was surprised to find birds belonging to this 
species. In all, twelve specimens were collected. I have 
not been able to compare them with specimens o£ Galerida t. 
cyrenaica from the type-locality, but they agree perfectly 
with the description of that race. This is the most easterly 
point in northern Africa at which these birds have been met. 
Wing of five males 94 to 100 mm., culmen 16-17. Wing 
of four females 91-95 mm., culmen 15-17. 
Note on the influences which tend to differentiate plumage 
colour among the Crested Larks . 
The Crested Larks of the Near East afford interesting 
evidence regarding the influences which tend to differentiate 
plumage colour. 
Beebe, when conducting experiments on some American 
Doves in captivity, found that artificial humidity produced 
darker plumaged and more variegated birds. 
Ogilvie-Grant found that rainfall seemed to be a factor 
among Bustard-Quail in south-eastern Asia in determining 
the darkness or otherwise of plumage. Similarly, the darker- 
plumaged Robins, Song-Thrushes, etc., of the British Islands, 
and the still darker Hebridean Song-Thrush, seem to be 
influenced by the greater rainfall in their homes. 
Through the kindness of the Egyptian Meteorological 
Department, I have been supplied with the following figures. 
I would point out that the percentage of humidity is the 
amount of moisture in the atmosphere, and has nothing to 
do with rainfall. Thinking that perhaps birds might be 
influenced by conditions during their actual breeding-season, 
I also worked out conditions for those months during which 
they breed, and the following are the results. 
The races of Galerida cristata are arranged, beginning 
with the darkest-plumaged birds and ending with the palest- 
plumaged birds :— 
