MYIODIOCTES.—BASILEUTERUS. 169 
forehead and chin being almost orange, by the greater brightness of the steel-blue 
gloss of the cap, and other minor characters. 
Dr. Coues 18, remarking on the distribution of these varieties, says that M. pileolatus 
is not restricted to the Pacific coast region, and that his Arizona specimens are precisely 
like Pennsylvanian ones. He therefore places both varieties under the same name; and 
we follow him in so doing; for though we recognize both races in our Central-American 
series of specimens, we are, like him, unable to trace their distribution definitely, and 
consequently leave the species undivided. If any thing, the so-called western race is 
most prevalent in Costa Rica and Panama—that is, at the extreme southern limit of the 
range of the species. This is contrary to what we usually find; for when two species or 
races inhabit the northern continent, it is the eastern and not the western form that has 
the most extended range in the winter season. 
Myiodioctes pusillus is a well-known Mexican and Guatemalan species in the winter 
months, being distributed all over the country, from near the sea-level to an altitude 
of 5000 or 6000 feet. At Duefias we used frequently to meet with it in second- 
growth woods and in willow trees on the banks of the Rio Guacalate. In Costa Rica 
Dr. v. Frantzius met with it between August and March, and as high as 7000 feet in 
the Poas volcano. Some of Carmiol’s specimens were obtained as late as April ®. 
In North America MW. pusillus is chiefly known as a bird of passage, its breeding- 
quarters extending northwards of Massachusetts, except in the higher mountains of the 
west 18. But little, however, has been recorded of its breeding-habits, and this long ago 
by Audubon and Nuttall, the former naturalist having described a nest he found in 
Labrador, and the latter one from Oregon. That this species breeds in the higher 
mountains of Nevada, Colorado, and Arizona there can be no doubt, as the testimony 
of Messrs. Ridgway and Henshaw, and also of Dr. Coues, indicates that it is found 
during the summer months in these regions; but as yet no nests have been discovered 
there 18. The eggs are described as white, finely sprinkled round the larger end with 
brownish red and lilac 1”. 
BASILEUTERUS. 
Basileuterus, Cabanis in Schomb. Reisen Guiana, iii. p. 666 (1848). (Type “ Sylvia vermivora, 
Vieillot,” auct.,= Basileuterus auricapillus (Sw.) apud Berlepsch, Ibis, 1881, p. 240.) 
In having a narrow nearly even tail of about the same length as the wings, and a 
broad depressed bill with well-developed rictal bristles, this genus resembles Myio- 
dioctes; but the wings are more rounded, and the first primary shorter; the culmen, 
too, is more curved. Moreover all the members of Myiodioctes are of migratory 
habits, and spend the summer in North America, and the winter in Central America ; 
whereas the species of Basileuterus are, so far as we know, of non-migratory habits, all 
belonging to the Neotropical region. 
Basileuterus is the largest genus of the Mniotiltide, containing more species than 
BIOL. CENTR.-AMER., Aves, Vol. I., October 1881. 22 
