46 SYLVIIDZ. 
Sialia wilsoni, Sw. Zool. Journ. iii. p. 173°; Scl. P. Z.S. 1856, p. 293°, 1858, p. 299", 1859, 
pp. 861", 371”; Scl. & Salv. Ibis, 1859, p. 8°, 1860, p. 29 “; Jones, Nat. Bermuda, pp. 28, 
66°; Taylor, Ibis, 1860, p. 110"; Owen, Ibis, 1861, p. 60 ur 
Sialia azurea?, Sw. Phil. Mag. new ser. i. p. 869 (descr. nulla!)"; Baird, Rev. Am. B. p. 62”; 
Sumichrast, Mem. Bost. Soc. N. H. i. p. 544”. 
Supra azurea, uropygio paulo letiore, genis vix obscurioribus; subtus rufo-castanea, ventre medio et crisso 
albis. Long. tota 6°5, ale 4-1, caude 2°8, rostri a rictu 0°75, tarsi 0°75. (Descr. maris ex Volcan de Agua, 
Guatemala. Mus. nostr.) 
Juv. supra fusca, interscapulio albo guttato ; subtus albescens, plumis (pracipue in pectore) rufo marginatis, alis 
et cauda cerulescentibus. (Descr. av. juv. ex Duefias, Guatemala. Mus. nostr.) 
Hab. Eastern Unitep States, west to Fort Laramie, north to Lake Winnipeg*.— 
Mexico, Real del Monte (Bullock'8), Cordova and Cerro del Gallego (Sailé*), 
valley of Mexico (le Strange), temperate region of Vera Cruz (Sumichrast*°), 
Jalapa (de Oca"), Mirador (Sartorius?), La Parada! and Juquila!? (Loucard) ; 
GUATEMALA, Quezaltenango, ridge above Totonicapam, Godines, Duefias™, San 
Gerdnimo"’, Tactic, Coban (0. S.& F. D. G.); Hoypuras (Taylor *)—Brruupa !; 
Cusa’. 
The common Bluebird of the Eastern States, which has been known to naturalists 
since the days of Catesby *, was described by Linnzeus under the name Motacilla sialis ; 
but Swainson, using Sialia for the generic name, proposed to call the bird S. wilsonz, 
by which it was long known. Prof. Baird restored the Linnean specific name whilst still 
retaining Swainson’s generic title, considering that the slight difference in the termi- 
nation of the two words was sufficient to justify such a course. The bird is now 
universally known as Sialia sialis by all American ornithologists; and we follow their 
practice. 
In his ‘ Synopsis of the Birds of Mexico’ !® Swainson seemed to consider the Mexican 
bird to be distinct from the northern one, and proposed for it the name Stalia azurea, 
but gave no description of it. This name Prof. Baird! adopted for the Mexican 
and Guatemalan bird, believing it to possess characters sufficiently pronounced to 
admit of its being considered distinct. We have carefully examined a number of 
specimens, to ascertain whether S. azurea can be distinguished with certainty; but 
we fail to find constant characters by which to detine it. Some Guatemalan examples 
have the chestnut colour more diffused over the under surface and are somewhat large ; 
but scarcely any difference is to be seen in the colour of the back when compared 
with specimens of true S. stalis; and the other points being variable, we doubt whether 
S. azurea deserves specific rank or is even to be considered a local form. 
S. sialis would appear to be a common bird in Mexico, though by no means go 
abundant in Texas®°°. In the State of Vera Cruz Prof. Sumichrast considers it to be 
unquestionably a resident, but not always found in the same localities; wherever it 
* Nat. Hist. Carol. i. p. 47, t. 47. 
