262 



BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



CORVUS CORAX SINUATUS (Wagler). 

 MEXICAN RAVEN. 



Similar to C. c. principalis, but averaging smaller, with relatively 

 smaller and narrower bill and longer and more slender tarsus. 



Adult male.— length (sldns), 618.1-694.3 (654.2); wing, 396.2-459.7 

 (430.8); tail, 218.4-2.54 (236.7); exposed culmen, 66-80 (74.4); depth 

 of bill at nostrils, 23.4-27.9 (25.6); tarsus, 64.8-73.7 (69.8); middle 

 toe, 39.4-58.4 (47.2); graduation of tail, 39.4-63.5 (48. 5). « 



Adult female. -heno;th (skins), 592.7-656.2 (631.6); wing, 386.1- 

 431.8 (408.9); tail, 208.3-251.5 (228.8); exposed culmen, 64.8-76.2 

 (69.8); depth of bill at nostrils, 22.9-27.4 (24.4); tarsus, 63.5-73.1 

 (66.8); middle toe, 40.1-47 (41.7); graduation of tail, 34.3-61 (48.5).^ 



Western United States in general and southward over plateau and 

 mountains of Mexico and Guatemala to pine region of northern Hon- 

 duras (between Opotelma and Seguatepeque). Range essentially coin- 

 cident with limits of arid division of the Upper and Lower Sonoran 

 or Austral life zones, but invading, locally, portions of the Boreal 

 "islands," and probably also, sporadically, the western and central 

 portions of the humid division of the Sonoran or Austral life zones 

 (to Missouri, southern Illinois, southern Indiana, etc.^). 



« Twenty-five specimens. 



^Twenty specimens. 



Specimens from Guatemala and southern Mexico are larger than those from 

 northern Mexico and the southwestern United States, as shown by the following 

 measurements: 



cAs stated on p. 260, the status of the ravens breeding east of the Great Plains and 

 south of the Great Lakes and St. Lawrence (except those of the Boreal islands of the 

 Appalachian Mountain district, which are almost certainly C. c. principalis) has not 

 been satisfactorily determined, owing to the difficulty of acquiring material for study. 

 The assignment of central Mississippi Valley records to C. c. simiatus and Atlantic 

 coast records to C. c. princijmlis is therefor purely provisional or tentative. 



