Occasionally these nests have been found at the height of ten feet from the ground, but they are more frequently built at a much greater elevation, even to the height of fifty feet or more. They are made in the shape of a truncated cone, three inches in diameter at the base and but two at the top, and three and a half inches in height. The diameter of the opening is an inch and a half. In Northern Georgia they nest about the middle of May, and are so abundant that the late Dr. Gerhardt would often find not less than five in a single day, and very rarely were any of them less than sixty feet from the ground. Dr. Gerhardt, who was an accurate and careful observer, speaks of these as the best built nests he had met with in this country, both in regard to strength and its ingeniously contrived aperture, so narrowed at the top that it is impossible for the eggs to roll out even in the severest wind. They have two broods in the season in the Southern States, one in April and again in July. This Flycatcher lays usually five eggs. These are of a short oval form, somewhat pointed at one end and rounded at the other, and measure .56 of an inch in length by .44 in breadth. Their ground-color is a greenish-white, marked and dotted with small blotches and spots of varying and blending shades of reddish-brown, lilac, and slate. Polioptila plumbea, BAIRD. LEAD-COLORED GNATCATCHER; ARIZONA GNATCATCHER. _Polioptila plumbea_, BAIRD, Pr. A. N. Sc. VII, June, 1854, 118.—IB. Birds N. Am. 1858, 382, pl. xxxiii, fig. 1; Review, 74.—COOPER, Birds Cal. 1, 37. SP. CHAR. Above bluish-gray; the forehead uniform with the crown. Eyelids white. A pale grayish-white line over the eye, above which is another of black, much concealed by the feathers, and which does not reach to the bill. Lower parts dull white, tinged with bluish on the sides and with brownish behind. Tail-feathers black; the first and second edged and tipped with white, involving the entire outer web of the first, and most of that of the second; the third with only a very faint edging of the same. Female duller, without the black superciliary line. Length, 4.40; wing, 1.80; tail, 2.30 (7,189). HAB. Arizona. This species differs from _P. cærulea_, in having the ash above less bluish, especially on the forehead; the black superciliary streak is only a horizontal bar, not reaching the bill, whereas in _cærulea_ it not only reaches the bill, but also extends across the forehead; the light superciliary stripe is more distinct. The tail is entirely different, the lateral feathers being almost entirely black, instead of the reverse. From immature specimens of _P. melanura_ it may be distinguished by larger size and purer white lower parts, and greater amount of white on outer webs of lateral tail-feathers.