“I was therefore surprised to meet with this species after sixty miles of travel on the Colorado desert near the Little Lagoon. It was perched on a _Mesquite_ tree, jerking its tail almost incessantly, as do various other species of Fly-catchers, and dashing occasionally in irregular curves and angles high into the air in pursuit of insects. On approaching the Colorado, this Fly-catcher became quite abundant, as I frequently saw companies of twenty or thirty together, many of which would be on the wing at the same time, engaged at their usual employment. At Fort Yuma, this species was also met with in considerable numbers late in November, when they were migrating southward. Its note is a low, plaintive whistle. This bird undoubtedly incubates in California, as I have seen specimens which were certainly very young birds, though I have not been so fortunate as to discover its nest.” Near Fort Webster, in New Mexico, Dr. Henry has seen this bird, though he considers it of rather rare occurrence. Dr. Kennerly noticed it in abundance during the months of February and March, on the route of Lieut. Whipple’s party, from the Big Sandy creek to the Great Colorado river. Our plate represents the adult male and female about two-thirds of the size of life. DESCRIPTION AND TECHNICAL OBSERVATIONS. Genus Ptilogonys. Swainson, Zool. Jour. III. p. 164. (1827.) Bill, moderate, wide at base, upper mandible curved towards the end, and distinctly notched; wings, moderate or rather long, first primary very short, or rudimentary; tail, long; legs and feet, moderate. General form, rather slender; head frequently with elongated crest-like feathers. Contains several species of birds, all of which are American. Ptilogonys nitens. Swainson. Lardner’s Cab. Cy. Birds, Pt. III. p. 285. (1838.) Form. Slender; crest-like feathers of the head much elongated; wings with the fifth and sixth quills longest and nearly equal; tail, long, graduated. Dimensions. Total length (of skin) about 7½ inches; wing, 3¾; tail, 4 inches. Colors. _Male._—Entire plumage glossy black, with a greenish lustre, except a spot on the inner web of each primary quill, occupying about the middle third of its length, which is pure white. Bill and feet, black. _Female._—Entire plumage, except the tail, cinereous, tinged with olive on the back and abdomen; superior wing coverts, and inferior tail coverts, edged and tipped with white. Quills, dark-brown—secondaries edged with white; tail, black, without lustre. _Young_—like the female; but in the males, with the spot on the primaries discernable, though more or less obscure. Hab. California, New Mexico and Mexico. Spec. in Mus. Acad. Philada., and Nat. Mus., Washington city.