Of the fifteen specimens collected only four have the bill wholly black. With all the others there is more or less flesh-color, which, although usually confined to the base and tip of the lower mandible, sometimes spreads over nearly the whole of the bill below as well as encroaching on the maxilla at the tomia, and occasionally even occupies a narrow central space along the ridge of the culmen above the nostrils. Mr. Henshaw has remarked on this feature, which he considers peculiar to young birds. If this view be correct it must require several years for the bill to become unicolor.
98. Eremophila alpestris chrysolæma (Wagl.) Coues. Mexican Shore Lark.—The only Shore Lark in the collection, a young bird in first plumage, taken on the plains at the base of the Santa Rita Mountains, has been referred by Mr. Ridgway to the above race.
99. Tyrannus verticalis Say. Arkansas Flycatcher.—Although this species was much less numerous than the following, especially after the spring migrants had gone, a few pairs were found breeding about Camp Lowell, where a nest containing three slightly incubated eggs was taken on June 20. The collection includes skins from Tucson and Camp Lowell.
100. Tyrannus vociferans Swains. Cassin’s Flycatcher.—“Abundant in summer. Neither verticalis nor vociferans winters in Arizona.” Specimens were collected at Tombstone, Tucson, and among the Santa Rita Mountains.
The peculiar attenuation of the primaries in this species has been freely commented on by authors, but no one seems to have noticed that this character, at least as applied in diagnoses, is to be found in only the male of T. vociferans. Nevertheless this is true of the somewhat large series of specimens before me, among which there is a decided and very constant sexual difference in the shape of the outer four primary feathers. All the adult males have them abruptly and deeply notched on the inner webs about half an inch from the tip, the emargination extending more than half-way to the shaft and reducing the width of the feather, terminally, to about .12 of an inch. In the females these feathers show no well-defined notching, the tips being simply tapered, usually with a slightly concave outline, although the outline is sometimes actually rounded. A young male from Riverside, California (No. 6380, Sept. 19, 1881), taken during its first autumnal moult, has the old primaries (1–2) almost without attenuation, their tips being only slightly tapered, while the new ones (3–5) are as deeply notched as in any of the adults. Hence it is probable that males in first plumage will be found to have the primaries shaped like those of the female.
The sexes of T. verticalis differ in a similar manner but less markedly, for the first primary of the female, although broader than that of the male, usually has the same falcate shape. I have one or two females, however, which, by the wing characters alone, can with difficulty be distinguished from females of vociferans.
101. Myiarchus mexicanus cooperi[[94]] (Kaup) Baird. Cooper’s Flycatcher.—This large Myiarchus which, as I lately announced,[[95]] Mr. Stephens has the credit of first finding within our boundaries, was ascertained to be a common summer resident about Camp Lowell. Of its occurrence in New Mexico, also, I now have positive evidence, a previously undetermined specimen, taken by Mr. Stephens near the Gila River, June 12, 1876, proving on comparison to be identical with the Arizona ones.
The collector’s notes relating to the habits of this Flycatcher are disappointingly brief. It frequented low mesquites and was tame and rather noisy, having a variety of loud calls, some of which resembled those of M. cinerescens, while others were “almost Thrasher-like.” Its food seemed to consist largely of beetles. On June 27 a nest was found at Camp Lowell. “Both parents were distinctly seen and positively identified. The nest was in an old Woodpecker’s hole in a giant cactus about eighteen feet from the ground. It was lined with soft, downy weed-seeds, and contained two young just hatched and an addled egg.” The egg, unfortunately, is so badly broken that accurate measurements are impossible, but an approximation would be 1.04 × .74. In ground-color and markings it closely resembles eggs of M. crinitus, the shell being a dull clayey-buff over which are numerous longitudinal lines and dashes of purplish-brown or lavender. These markings are pretty evenly distributed, but are coarsest at the larger end of the egg.
462, ♂ ad., Camp Lowell, May 31. Length, 9.90; extent, 14.10; wing, 4.40; tail, 4.40; culmen, 1.15. “Iris brown; bill and legs black.”
468, ♂ ad., Camp Lowell, June 1. Length, 10; extent, 14.30; wing, 4.35; tail, 4.44; culmen, 1.10.