190 HORNED LARKS OF THE COLORADO BASIN 



generally throughout British America, and migrating into the United States 

 in the fall, to leave again in the spring. Those birds which breed in the United 

 States, in the open country between Iowa, Wisconsin, and Minnesota and 

 the Rocky Mountains, north of about 40, and are resident to some degree 

 on those plains, have acquired certain recognizable peculiarities which stamp 

 them as a geographical race. This form has been occasionally mentioned by 

 late writers under the name of "occidentalis ", which I observe is retained 

 in the "History of North American Birds " (ii. p. 140). But Colonel McCall's 

 description was based upon a bird from Santa Fe, New Mexico, and is there- 

 fore most probably applicable to chrysolcema, where also belong the other spe- 

 cific names which have been imposed upon our Western Larks. A new name 

 being apparently required, I called this var. leucolcvma in the work above 

 mentioned. Var. chrysolcema is more decidedly different in the points already 

 given. Some of the specimens before me, labeled " California ", but probably 

 either from Lower California or Mexico, are so strongly marked that, in the 

 absence of connecting links, I should give it specific rank. Many inter- 

 mediate examples are, however, forthcoming. 



Specimens from the northerly portions of the Pacific coast regions are said 

 to be nearer typical alpestris, but even darker than that form, and thus still 

 further removed from either leucolcema or chrysolcema. 



Lacking opportunity at present of reviewing the case of E. pcregrina of 

 New Granada (Scl. PZS. 1855, 160, pi. 102, Bogota), which is held to be speci- 

 fically distinct by several high authorities, I have omitted the references to 

 it, though in the " Birds of the Northwest" I added them to those of chryso- 

 lcema, judging it to be only the extreme of differentiation which the latter 

 has sustained. 



The preparation of exact synonymy in the present case has proved a mat- 

 ter of some difficulty, especially since the case has been complicated by the 

 introduction of var. leucolcema. When other clue was wanting, I have col- 

 lated the quotations mainly upon geographical considerations, not always, 

 however, satisfactory. For many of the references are actually more com- 

 prehensive than my collation would imply, since they include the varieties, 

 especially var. leucolcema ; in other cases, geographically restricted, it is still 

 uncertain which variety a writer had in view, since both may be found asso- 

 ciated at some seasons. I have been obliged to query some references, and 

 take others " upon their face", according to the name used. 



RESPECTING more particularly the Larks of the Colorado 

 Basin, it should be observed that the birds which breed 

 within this area are, probably without exception, referable to 

 the var. chrysolcema^ even though the peculiarities in ay not always 

 be as strongly expressed as they are in those which breed fur- 

 ther south. This form is abundantly distributed in suitable 

 localities, and resident. With the fall migration, however, 

 northern-bred birds of the other variety (leucolcema} enter this 

 region, and the two may be found associated. No difference 

 in habits has been observed. 



