The Mexican species yet discovered are of very fine plumage, though generally of smaller size than many of those of South America. Several of the species of the southern portion of this continent are, in fact, so large that they approach the stature of their relatives, the crows, though clothed in a quite different style of vesture. In fact, some of the larger species are known to collectors and travellers by such names as the Blue crow, the Surinam crow, &c. The _Cyanocorax azureus_ of South America is the “Blue Crow,” and is one of the largest species of this family. The Jays must be regarded as highly organized birds, and are possessed of a superior order of instincts. However deficient in melody or compass of voice, there are few other birds in which are found combined so many characters or bird-like qualities. Delicacy of form, beauty of plumage, vigorous and enduring powers of flight, are united with much liveliness of disposition, unusual instincts of precaution and self-preservation, and the ability to subsist on very diversified descriptions of both animal and vegetable food. They are accordingly entitled to a superior position in any system of classification, based, as all zoological systems should be, on the knowledge of functional as well as of organic characters;—on the observations of the naturalist in the field or forest, not less than on the conclusions or discoveries of the anatomist. Nearly all the species of this group of birds appear to partake to a considerable extent of the cunning, though not unpleasant nor unsociable habits of the Blue Jay of the United States, and like it they feed indiscriminately on seeds or fruits, worms, insects, and even small quadrupeds, or on other birds. They live principally in the forests, though several of the fine species of South America and all the species of North America frequently resort to the orchards and fields, or approach the habitations of men, and when captured young are readily domesticated. The very handsome bird which, in our first plate, we present to our readers, is a recent addition to the Ornithology of the United States, having been observed in Texas, though previously known as a bird of Mexico. It is nearly related to the Peruvian Jay, _C. yucas_, Boddaert, or _C. peruvianus_, Gmelin, which is a native of the countries of western South America. It is, however, considerably smaller, and is differently colored on the inferior parts of the body, having there a prevailing tint of green instead of the clear yellow of that also handsome bird, and other characters tending to establish a clear specific difference.