BREW'STEE : BIRDS OF THE CAPE REGION, LOWER CALIFORNIA. 169 



Tachycineta thalassina lepida. 



Date 

 April 19, 1885 

 20, 1886 



(( U If 



26, 1885 



3, 1878 



10, 1880 



30, 1883 



3, 1878 



24, 1888 



12, 1888 



5, 1897 



9, 1891 



8, 1888 

 10, 1871 



ti it 

 (< a 



(< it 



9, 1879 



May 



Sept. 



April 



March 



Sept. 



May 



April 



May 



April 



June 



July 



May 



675 1 $ Mill City, Col. 



5,899 1 ? Cienega Station, Arizona 



676 1 9 Marin Co., Cal. 

 33,298 2 9 Nicasio, Cal. 



Average, 



May 

 April 

 June 

 April 



Average, 



24, 1877 

 16, 1881 

 12, 1877 

 12, 1879 



Wing 



4.62 



4.51 



4.50 



4 26 



4.57 



4.53 



4.52 



4.43 



4.58 



4.80 



4.72 



4.50 



4.50 



4 54 



4.51 



4.50 



4.45 



4.78 



4.70 



4.54 

 4.28 

 4.10 

 4.41 



Tail 

 1.92 

 1.87 

 1.94 

 1.90 

 1.95 

 1.86 

 1.98 

 1.93 

 1.89 

 1.80 

 2.00 

 1.80 

 1.90 

 1.99 

 1.75 

 1.90 

 1.80 

 1.98 

 1.95 



4.55+ 1.904- 



1.89 

 1.79 

 1.73 

 1.72 



4.33+ 1.78+ 



The Violet-green Swallow of the Cape Region furnishes an interesting illus- 

 tration of the recognized fact that isolated, non-migratory birds are given to 

 having shorter wings than those which regularly perform extended journeys, 

 for in respect to the length of the wing it is almost if not quite as much smaller 

 than the form which breeds in the regions lying further to the northward 

 (i. e. California, Oregon, Washington, and British Columbia) as the latter is 

 smaller than true thalassina of the Mexican table-land still further to the 

 southward. This difference, shown in the foregoing tables of measurements, 

 is the only essential one which I am able to find between lepida and brachyp- 

 tcra. In the material which I have examined it appears to be not only marked 

 but constant. There can be little question, however, that the two birds really 

 come together and intergrade in the central portions of the Peninsula. 



1 Collection William Brewster. 



2 Collection Mus. Comp. Zool. 



