380 
I!. S. P. E. R. EXP. AND SURVEYS ZOOLOGY — GENERAL REPORT 
Comparative measurements of species. 
Catal. 
No. 
Length. Stretch 
1 of winfts. 
Middle Its claw Bill 
toe. alone, above. 
Along 
gape. 
S|)eeimen 
measured. 
10214 I Polioptila caerule 
616 do 
7191 j Polioptila mela 
7192 do 
7187 Polioptila plum 
.do. 
do. 
South Illinois 
Washington, D.C 
Tort Yuma.. 
l!oc;i Grande, Mf.\ 
Camp 119.. 
do ... 
Mexico.... 
4.60 
4.50 
4. CO 
4.16 
4.20 
4.50 
5.110 
4.40 
4.00 
4.44 
. Q.06 
. 2.10 
2 10 
2.04 
2.18 
2.20 
0.62 
0.G7 
0.64 
0.65 
0.12 
0.14 
0.48 
0.44 
0.43 t 0.13 
0.38 
0.43 
0.42 
0.44 i 0.12 0.28 
0.47 ! 0.11 0.44 
0.52 
0.54 
Skin. . 
Skin.. 
Skin. . 
Fresh. 
Skin.. 
Fresh . 
Skin. . 
POLIOPTILA CAE RULE A, Sclater. 
Blue-Gray Flycatcher. 
Moladlla caerulea, Linnaeus, Syst. Nat. 1, 176(5, 43. — Gmelin, I, 1788, 992. 
Sylvia caerulea, Lath. hid. Orn. II, 1790.— Vieillot, Ois. Am. Sept. II, 1807, 30; pi. Ixxxviii.— Bon. Obs. Wils. 
1825, No. 119. 
Muscicapa caerulea, Wilson, Am. Orn. II, 1810, 1G4 ; pi. xviii, f. 3— Aud. Orn. Biog. I, 183), 431; pi. 84.— 
Nuttall, I, 1832, 297. 
Culicivora caerulea. Bon List, 1838.— Ib. Consp. 1850.— Aud. Syn. 1839, 42.— Ib. Birds Amer. I, 1840, 244 ; pi. 70. 
Sxjlvania caerulea, Nuttai.i., Man. I. 2d ed. 1840, 337. 
Polioptila caerulea, Sclater, Pr. Zool. Soc. 1855, 11. 
Motacilla cana, Gmei.i.v, Syst. Nat. I, 1788, 973. 
Sylvia cane,, Latham, Ind. Orn. II, 1790, 543. 
? Culicivora mexicana, Bonap. Consp. 1850, 316. Female. (Not of Cassin.) 
S'p Ch. — Above grayish blue, gradually becoming bright blue on the crown. A narrow frontal band of black extending 
backwards over the eye. Under parts and lores bluish white tinged witli lead color on the sides First and second tail feathers 
white except at the extreme base, which is black, the color extending obliquely forward on the inner web : third and fourth 
black, with white tip, very slight on the latter ; fifth and sixth entirely black. Upper tail coverts blackish plumbeous. Quills 
edged externally with pale bluL-.h gray, which is much broader and nearly white on the tertials. Female without any black 
onthehead. Length, 4.311 ; wing, 2. 15 ; tail, 2.25. (Skin.) 
Hdb. — United States from Atlantic to Missouri, and on the southern border from the Gulf of Mexico to the coast mountains 
of California. South to Guatemala. 
In addition to the above characters there is a narrow white ring round the eye. The lores 
are rather paler than the cheeks. The black above the eye runs out into a point a little 
behind it. 
The exposed portion of the first or spurious quill is less than half that of the second. This is 
intermediate between the seventh and eighth. The fourth quill is rather longer than the third 
and fifth. The narrow tail feathers are long and linear. They are moderately graduated; the 
outer about a quarter of an inch less than the middle. 
Specimens vary somewhat in the amount of black on the forehead, as well as the purity of 
the whitish on the tertiaries. All the white feathers of the tail have black shafts, sometimes 
the white tip of the fourth feather is wanting. The feathers of the rump are decidedly whitish 
towards their base, though this is not visible except when they are separated. Some entirely 
white are concealed by the others. 
Specimens from Tamaulipas differ in a more attenuated bill, and in having the black super- 
ciliary line bordered below on the lores and before and above the eyes by bluish white, rather 
