6 
Hen sh AAV on the Species of the Genus P-cisserella. 
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 befen 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 
