6 Henshaw on the Species of the Genus Passerella. 



known with certainty. It seems probable that they do, and certain 

 specimens, now to be noted, suggest in their intermediate char- 

 acters such a union of the respective regions. These are comprised 

 in a series of sixteen specimens collected in California by myself 

 during the fall of 1875. While these are all referable to town- 

 sendi, not one is typically like that bird, as its characters are illus- 

 trated by many examples in the Smithsonian from Sitka, Kodiak, 

 and the contiguous regions. The variation inclines from a quite 

 near approach to the dark olive-brown of townsendi, with its un- 

 streaked dorsum, to a shade approaching suspiciously close to the 

 ferruginous color of iliaca ; these latter individuals show appreci- 

 able though obsolete streakings on the back, and may be fairly 

 compared with the latter bird. In this connection a single speci- 

 men in the Smithsonian Collection from California is very inter- 

 esting, since it was named " iliaca " by Mr. Ridgway, and thought 

 to be a straggler of this species. On the strength of this speci- 

 men, Dr. Coues, in his " Birds of the Northwest," gives iliaca as 

 " accidental in California." In the light of the series now at hand 

 the specimen in question assumes a new significance, and is seen to 

 exhibit but a somewhat nearer approach to iliaca than the extreme 

 of the above suite ; with them it is to be considered as indicating the 

 intermediate condition of color between the two, and hence of their 

 intergradation. 



If the same test be applied to schistacea and townsendi it results, 

 without going into unnecessary details, in the same way. Their 

 complete inosculation as to color may readily be proven. A series 

 of measurements to illustrate the relation in size of the four forms 

 gives the average of the parts as follows. Space forbids our giving 

 full tables of measurements, as would have been desirable. 



P. iliaca. Average of ten specimens from Eastern United States, Alaska, 



etc. : wing, 3.40 ; tail, 3.07 ; bill, .32 ; tarsus, .93. 

 P, townsendi. Average of twenty- three specimens : wing, 3.20 ; tail, 3.15 ; 



bill, .49 ; tarsus, .94. 

 P. schistacea. Average of nine specimens : wing, 3.13 ; tail, 3.37 ; bill, 



.44 ; tarsus, .91. 

 P. megarhyncha. Average of eight specimens : wing, 3.21 ; tail, 3.58 ; bill, 



.51 ; tarsus, .93. 



As will be seen from the above-given average measurements, 

 iliaca and townsendi agree in having the wing longer than (in some 



