SAYORNIS. 65 
This species appears to be found throughout Mexico as far as the south-western 
confines of that country, but as yet we have no record of it or of the allied form in 
Yucatan *. | | | | _ 
Sumichrast states that it is a very common species in the temperate and colder parts 
of the State of Vera Cruz, and that it builds its nest in the houses of Orizaba?. It is 
not, however, solely confined to these districts, for both Grayson ® and Forrer met with 
it near the sea-level in the vicinity of Mazatlan. 
It frequents the banks of streams, and most of its insect prey is taken from near the 
surface of the water. It buildsa nest with an outer wall of mud like that of a Swallow ; 
this is fastened to a wall or placed on a shelf, beam, or ledge of rock, with an over- 
hanging projection to protect it from rain. The nest is lined with fine grass or moss 
and horse- or cow-hair. The eggs are pure white. 
S. nigricans appears to be resident in Mexico and also in Arizona and California, but 
in more northern districts where its insect food fails in the cold weather it is a summer 
visitor, migrating southwards at the approach of winter. © 
4. Sayornis aquatica. 
Sayornis aquatica, Scl. & Salv. Ibis, 1859, p. 119*; Lawr. Ann. Lyc. N. Y. ix. p. 110°; v. Frantz. 
J. £. Orn. 1869, p. 806°; Boucard, P. Z. S. 1878, p. 62°; Scl. Cat. Birds Brit. Mus. xiv. p. 33°. 
Aulanax aquatica, Cab. J. f. Orn. 1861, p. 247 °. 
Sayornis nigricans, Bp. Compt. Rend. xxxviii. p. 657"; Notes Orn. p. 87°. 
S. nigricanti similis, sed crisso fuliginoso distinguenda. 
Hab. GuaTEMALA, Quezaltenango, Duefias!, Retalhuleu, Escuintla, R. Michatoya near 
San Pedro Martyr, San Gerénimo (0. 8S. & F. D. G.); Nicaragua (Delattre’ 8) ; 
Costa Rica (v. Frantzius?®, Arcé, A. R. Endres), San José (Boucard *). 
Sayornis aquatica takes the place of S. nigricans in. Guatemala. and the rest of 
Central America as far south as Costa Rica, and may be recognized by its dusky under 
tail-coverts, those of the allied form being white. In the north-western parts of South 
America another form of Sayornis occurs with dusky under tail-coverts, 8. cineracea 
(Lafr.), but may be distinguished by the broader white edgings to its wings and tail 
and its blacker plumage. . ; 
S. aquatica is a familiar bird in many parts of Guatemala, where, like its congener, 
it frequents streams, often resting on a stone on the margin or even surrounded by 
water; from such a point of observation it will fly suddenly and seize passing insects. 
In its general habits it is more active than Tyrant Flycatchers usually are, and may not 
unfrequently be seen about houses, some running stream being near. We never met 
with the nest of this species. 
* Brewer states that S. negricans is resident in Guatemala, and he quotes Salvin as his authority, adding 
that the note may refer to S. aquatica ; a curious inaccuracy, as the passage quoted is appended to the original 
description of S. aquatica, no mention whatever being made of S. nigricans: 
BIOL. CENTR.-AMER., Aves, Vol. II., February 1889. | 9 
