NO. 1916. REVISION OF BVTORIDES VIRESCENS—OBERUOLSER. 



547 



white and dark brown; breast, sides, and axillars rather h^dit gray, 

 about No. 7,* with a sh<;ht brownish tinge; abdomen and crissum 

 mucli paler gray, somewhat mixed with whitish, particularly on 

 latter, whicli have slate-colored terminal or subterminal spots or 

 blotches; thighs pale gray, with an ochraceous tinge exteriorly; lin- 

 ing of ^ving mottled pale gray and white, with a slight buffy wash, the 

 edge of ^ving broadly white. 



Measurements. — Male:^ Wing, 181-183 (average, 182) mm.; tail, 

 65-67.5 (66.3); exposed culmen, 57.5-63 (60.3); height of bill 

 at base, 11-12.5 (11.8); tarsus, 51.5-52.5 (52); middle toe, 46.5-48 

 (47.3). 



Female: Wing,' 182 mm.; tail, 65; exposed culmen, 54; height 

 of bill at base, 12; tarsus, 50; middle toe, 46. 



Type-locality. — San Diego, Chihuahua, Mexico. 



Geographical distribution. — Northern central Mexico: north to San 

 Diego, central Cliihuahua; south to Rio Scstin, northwestern Durango; 

 and in winter to Los Reyes, w^estern Michoacan. 



The present form is distinguishable from Butorides virescens vires- 

 cens by its much jialer posterior lower })arts, and more maroon tinged, 

 less purplish, and somewhat lighter neck and sides of head. Although 

 we have examined only a small number of specimens, the characters 

 exliibited by them seem to separate them subspecifically from both 

 Butorides virescens virescens and Butorides virescens anthonyi, the 

 forms wliich are geograpliically nearest. A single immature female 

 (No. 185244, U.S.N.M.) from Los Reyes, Michoacan, taken February 

 12, 1903, is apparently of tliis race, indicating its probable winter 

 range. 



Three specimens have been available, from the following places, 

 breetUng birds with an asterisk: 



Chihuahua. — San Diego.* 



Durango. — Rio Sestin.* 



Michoacan. — Los Reyes (February 12). 



' Of Mr. Ridgway's Xoinendalure of Colors, 18S6. 

 2 Two specimens, from Chihuahua and Durango. 

 ' One specimen, from Michoacan, -Mexico. 



* Used in measurement averages on p. .'>47. 



* Type, from San Diego, Chihuahua, Mexico, collected by F. Roblnette. 



* From Rio Sestin, Durango, Mexico, collected by J. H. Batty. 



' From Los Reyes, Mlcboacan, Mexico, collected by E. W. Nelson and E. A- Goldman. 



