males: Wing, 70.5 mm.; tail, 70.2;
exposed culmen, 8.6; depth of bill at base, 3.8. For extremes, see
accompanying table.

_Note._--In this paper the length of wing is the usual chord of the
folded wing as dried at the side of the body in the conventional study
skin. The tail length, however, is measured from the _base_ of the
uropygium to the tip of the longest pair of rectrices. It is found that
in preparing specimens there is a practically uniform place for cutting
off from the body the uropygium with attached feathers, and this is
exactly where the tail bends back at an angle to the body in the fresh
bird. The lateral rectrices are rooted evenly with the base of the dried
uropygium so that the measurement of tail length thus taken becomes the
distance from the extreme proximal ends of the most lateral pair of
rectrices to the tips of the central pair--somewhat greater than the
length of tail as given by Ridgway (1901, p. xv), the latter being the
measurement from the base of the central pair of tail feathers to the
tips of same. My reason for adopting this different procedure here is
that more accuracy seems possible thereby, at least in the kind of
material here dealt with. There is less mussing of the specimen also.

Neither depth of bill nor culmen is a practical index to degree of
slenderness of bill. No ordinary method of measurement will suffice to
indicate the facts as they are perceived by the eye.

As will be seen by the dates in the tables, as a rule only unworn
specimens have been selected for measurement.

_Range._--The Rocky Mountain region of North. America, from
eastern British Columbia and western Alberta south to western Texas,
New Mexico and Arizona. _Specimens examined_, 72, from the following
localities:

Alberta: Smoky Valley, 50 miles north of Jasper House, 1; Henry House, 1;
15 miles west of Henry House, 1.

British Columbia: South fork of Moose River, 1.

Montana: Gallatin County: Jefferson River, 1; Madison River, 2;
Hillsdale, 2; Mystic Lake, 1; Dry Creek, 1.

Idaho: Sawtooth Lake, 1.

Wyoming: Mammoth Hot Springs, 3; Jackey's Creek, 4 miles southwest of
Dubois, 1; Teton Pass, 7200 ft., 2; Salt River Mts., head of Dry Creek,
9200 ft., 1; Medicine Bow Mts., 10 200[**10,200-see Twining NM below]
ft., 1; Medicine Bow Creek, 1.

Utah: Filmore, 1.

Colorado: Loveland, 1; Middle Park, 1; Sangre de Christo Pass, 1; Fort
Garland, 1; Platte Canyon, 1; Pueblo, 2; Estes Park, 1; Boulder