Colors. Head black, which color has a semicircular termination on the breast. Entire under parts and neck behind, bright yellow; back and rump yellowish-green; wings black; quills edged externally with ashy white; tail black; bill bluish-black, lighter at the base of the lower mandible; tarsi and feet lead-colored; irides brown. Sexes nearly alike; female with the yellow parts of the plumage less vivid, and the tail in some specimens edged and tinged with greenish. Hab. Texas, Mexico. Spec. in Mus. Acad., Philada.; and Nat. Mus., Washington city. Obs. This bird resembles no other in any considerable degree; and is, therefore, to be easily distinguished. It seems to belong to some one of the subdivisions of the old genus _Icterus_, or of _Xanthornus_, which are so variously and confusedly given by professed systematists, that we have no faith in any of them; which declaration, by the way, we have no objection to embrace the present opportunity of extending to late _opinionative_ classifications, in a manner rather general and comprehensive. It is about full time for a true zoologist to appear, who shall be capable of systematizing—of reducing to order and symmetry the vast fund of facts and detached knowledge in natural history, which the present age has accumulated. In our happier day-dreams, we have deemed it inevitable that such a one must shortly appear. The great Anglo-Saxon zoologist is yet to come. [Illustration: Plate 22 The Purple-throated Humming Bird Trochilus Alexandri (_Bourcier_)] TROCHILUS ALEXANDRI.—Bourcier and Mulsant. The Purple-throated Humming Bird. PLATE XXII.—Adult Males. The Humming Birds are peculiar to America. Until within a comparatively recent period, about one hundred species were known to naturalists,—that being the then considered large number enumerated in works published as lately as within about twenty years. Discoveries of previously unknown species in this family of birds have been numerous beyond precedent or comparison with any other, notwithstanding the zeal and ability which ornithology has commanded within the period mentioned. At present, there are nearly three hundred ascertained species of Humming Birds. The large and recent additions have resulted, in a great measure, from the exploration of regions previously little visited or inaccessible, principally in the northern part of South America, but also in Central America and Mexico.