52 SYLVIIDZ. 
It seldom happens that male birds with the black forehead and eye-streak are found 
in Mexico and Guatemala; and this fact has given rise to the supposition that the bird 
found in these countries, for which Bonaparte gave the name P. mexicana, is a species 
distinct from P. cwrulea. My. Sclater, in 1859, thought that the black marks in the 
male were only assumed during the breeding-season. If this is really so, we know of 
no parallel case of such a change taking place in Passerine birds; but the suggestion 
receives support from the fact that one of our specimens with the black frontal line was 
shot at Lanquin in March. Dr. Gundlach, however, speaks very positively on the 
point, stating that the character which distinguishes the male from the female is only 
to be observed in spring shortly before the departure of the birds from Cuba for the 
United States in April 1°. 
2. Polioptila nigriceps. 
Polioptila nigricens, Baird, Rev. Am. Birds, p. 69°; Lawr. Mem. Bost. Soc. N. H. ii. p. 267°; 
Bull. U.S. Nat. Mus. no. 4, p. 12°. ; 
P. cerulee similis, sed pileo toto cum loris et superciliis nitenti-nigris. Long. tota 4:3, ale 1-95, caude 2:0, 
rostri a rictu 0°65, tarsi 0°75. (Descr. maris ex La Union, San Salvador. Mus. nostr.) 
Hab. Mexico, Mazatlan (Xantus!, Grayson ?), Tepic (Grayson ?), Quiotepec (Oaxaca), 
Tapana and Santa Efigenia (Tehuantepec) (Sumichrast *) ; San Satvapor, La Union 
(O. S.).—CoLoMBIA; VENEZUELA. 
Having had, through the kindness of the authorities of the Smithsonian Institution, 
an opportunity of examining the type specimen of Polioptila nigriceps and of comparing 
it with Colombian and Venezuelan examples some time called P. buffoni, we were 
unable to appreciate any tangible differences between them. Both have the lores black ; 
and in the amount of black on the outer rectrices both were almost exactly alike. We 
are therefore obliged to acknowledge them to be of one species. The La-Union 
specimen described above has a few white feathers in the lores, but does not otherwise 
differ from the type of P. nigriceps. The true P. buffoni is from Guiana, and has, as stated 
in Mr. Sclater’s original description, the outer rectrix nearly wholly white. The name 
P. mgriceps, therefore, can be used for the bird having the range indicated above. It 
is stated by Grayson? to be found in North-west Mexico in low brushy woods at all 
seasons, and by Prof. Sumichrast? to be common almost everywhere in the west of the 
Isthmus of Tehuantepec and in dry warm districts of the State of Oaxaca, frequenting 
the ravines and thin woods and going almost always in pairs. 
3. Polioptila bilineata. 
Culicwora bilineata, Bp. Consp. i. p, 816". 
Polioptila bilineata, Scl. P. Z.S. 1860, p. 273°; Baird, Rev. Am, B. i. p. 72°. 
Polioptila superciliaris, Lawr. Ann. Lyc. N. Y. vii. pp. 804‘, 822°, viii. p. 179°, ix. p. 9275 Scl. 
