170 . MNIOTILTIDA. 
even Dendreca. We aré now acquainted with twenty-seven species, which are widely 
distributed throughout Tropical South America, from South Brazil to Mexico. The 
countries including the Andes possess the greater proportion of the species; but Central 
America is well represented by eight species, only two of which (B. bivittatus and 
B. mesochrysus) have been found outside our limits. Mexico has three species— 
B. culicivorus, B. belli, and B. rufifrons; Guatemala the same number, B. delattrii 
taking the place of B. rufifrons. Costa Rica and Panama have five species—the two 
southern ones B. bivittatus and B. mesochrysus, B. melanogenys and B. leucopygius both 
peculiar, and B. culicivorus in common with Mexico and Guatemala. 
These eight species seem divisible into three groups, all of which are represented in 
South America, where others are also found. Prof. Baird has divided the genus into 
three subgenera, which he calls Bastleuterus, Idiotes, and Myiothlypis; but the lines of 
demarcation between them are so indefinite that we prefer to retain the use of the 
name Lasileuterus in its wide sense, and to group the species in sections. 
a. Pileus medius flavus aut aurantiacus, utringue nigro marginatus; gene 
nec nigre nec castanee. 
1. Basileuterus bivittatus. 
Muscicapa bivittata, d’Orb. & Lafr. Syn. Av. i. p. 51°. 
Muscicapara bivittata, d’Orb. Voy. Am. Mér. Ois. p. 8247. 
Basileuterus bivitiatus, Scl. P. Z. 8.1859, p. 187°; 1860, p. 85+; Salv. Ibis, 1870, p.108°; P.Z. 8. 
1870, p. 183°; Scl. & Salv. P. Z. 8S. 1879, p. 5947. 
Myiodioctes tristriatus, Tsch. Faun. Per. p. 193, t. 12. f.1°. 
Basileuterus melanotis, Lawr. Aun. Lyc. N.Y. ix. p. 95°; Salv. Ibis, 1869, p. 313°; v. Frantzius, 
J. f. Orn. 1869, p. 294". 
Supra olivacea, pileo medio aurantiaco-cinereo utrinque late nigro marginato, superciliis sordide albis, loris 
posticis et regione parotica nigris; subtus sordide flavicante, hypochondriis nigris olivaceo indutis; rostri 
maxilla corylina, mandibula albicante; pedibus pallide corylinis. Long. tota 5:0, ale 2°5, caude 2°3, 
rostri a rictu 0-6, tarsi 0°8. (Descr. exempl. ex Costa Rica. Mus. nostr.) 
Hab. Costa Rica (Van Patten), Cervantes (J. Carmiol®), Birris (v. Frantzius®); Panama, 
Cordillera del Chucu (Arcé > °).—Cotomaia®; Ecuapor?4; Prru’; Borrvia!27, 
This southern species is by no means common in Central America, where it has been 
found in Costa Rica and in the State of Panama. ‘The first Costa-Rica specimens which 
came into Mr. Lawrence’s hands were described by him as a new species under the name 
B. melanotis® ; but on receipt of specimens from the State of Panama we were enabled 
to compare them with South-American examples attributed to B. bivittatus, and found 
them not separable®. Since then we have obtained a Costa-Rica example and a much 
more extensive series from South America, including two from Simacu in Bolivia’, the 
country of the true B. bivittatus. In this series there is a certain amount of variation 
in the colouring of the central portion of the vertex, and in the amount of black 
