146 BULLETIN 61, UNITED STATES NATIONAL MUSEUM. 



Yarrow's (1883, 152) subspecies plutonia was based on melanistic 

 specimens, as were also those wliich he (1875, 554) referred to E. 

 vagrans angustirostris (Kennicott) and E. henshawi Yarrow (1883, 

 152). Melanism is more than usually common in the form. It is 

 of interest that three specimens (No. 1133) in the Field Museum of 

 Natural History from Grand Junction, Colorado, are all melanistic, 

 and correspond closely to those listed by Cope as inlutonia. As far 

 as our present knowledge goes, the only definite geographical varia- 

 tion in color is an increase in black pigment in the Sierra Nevada- 

 Cascade individuals, and a tendency toward an increased width of 

 the dorsal stripe on the west slope of the Sierra Nevadas. 



Affinities. — I have already stated that I believe elegans to be directly 

 related to hammondi, which it meets in southern California. There 

 are no apparent differences between the two forms which insure a 

 certain distinction of the specimens in the intermediate region. The 

 reason why 'some writers have insisted upon the distinctness of the 

 two forms is because they have generally laid stress upon a single 

 character in diagnosing their specimens. It has already been shown 

 that although liammondi'is usually characterized by 21-19-17 dorsal 

 scale rows, two preoculars, the absence of a dorsal stripe, and no defi- 

 nite spots on scales, in the northern part of its range 19-21-19-17 

 scale rows, one preocular, and a dorsal stri^^e often occur; while elegans 

 in the same region may have either 19-21-19-17 or 21-19-17 dorsal 

 rows. The reason why elegans apparently does not exhibit two 

 preoculars and an obsolete dorsal stripe in the southern part of its 

 range may very well be due to the fact that specimens with these 

 traits are referred to hammondi. 



The fact that the characters may seemingly occur in any combina- 

 tion in the intermediate region leads one to suspicion that an inter- 

 grading actually takes place, and that the differences between the 

 specimens are individual and not racial. However, this controverti- 

 ble point can not be decided imtil a large series of specimens with 

 detailed habitat notes has been obtained from the intermediate 

 region. But whether or not intergrading occurs, I believe that there 

 can be little question that the two forms are directly related. This 

 belief is confirmed by the reduction in the number of scale rows in 

 Jiammondi toward that part of the range of elegans with which it comes 

 in contact and by the fact that it is only in the western part of its 

 range that elegans possesses two preoculars. I have already called 

 attention to the fact that in the Sierra Nevada-Cascade range elegans 

 often has two plates in front of the eye, so frequent a trait in ham- 

 mondi, and it is only necessary to note here that if elegans has been 

 derived from hammondi the resemblance of the former to the latter 

 should be the strongest along this range, as it is a highway for mois- 

 ture-loving forms from southern California northward. If this 

 explanation is the true one, the Sierra Nevada-Cascade range may 



