There is considerable variation in adult males, especially in the width of the pectoral collar; one (No. 60,877, Mt. Carmel, Wabash Co., Ill., Aug. 9) has this entirely interrupted. In this individual there is no trace of a whitish supra-auricular streak; while others from the same locality, and obtained at the same date, have the band across the jugulum continuous, and a quite distinct white streak over the ear-coverts. HABITS. Of this somewhat rare Warbler very little is as yet well known. Its habits and distribution during the breeding-season need more light than we now possess to enable us to give its story with any degree of exactness. Its appearance in Pennsylvania, Ohio, Illinois, and Missouri early in May, when Warblers that go north to breed are on their way, at first suggested its belonging to that class. It is not known to proceed any farther north, except in accidental instances; though the writer has been assured, and has no reason to doubt the fact, that it abounds and breeds in the neighborhood of Niagara Falls. I can find no good evidence that it ever occurs in Massachusetts. Individuals have been obtained in northern South America, Panama, and Cuba. Dr. Woodhouse describes it as quite common in Texas and in the Indian Territory, where it breeds, as he obtained both the old and the young birds. It was also abundant among the timbered lands of the Arkansas and its tributaries. It was not obtained in any other of the government expeditions, nor was it found in Arizona by Dr. Coues. Mr. T. M. Trippe noticed a single individual near Orange, N. Y. Wilson supposed them to breed in Pennsylvania, though he was never able to find their nests. He usually met with these birds in marshes or on the borders of streams among the branches of poplars. Their habits were those of the Flycatchers. He saw none later than the 20th of August. Describing this species as the Blue-green Warbler, as met with by him on the banks of the Cumberland early in April, he mentions its gleaning for food among the upper branches of the tallest trees, rendering it difficult to be procured. Its resemblance, in habits, to Flycatchers, he again remarks. Its only note was a feeble _cheep_. According to Audubon, this Warbler appears in Louisiana, where it also breeds early in spring, and leaves the first of October. Like all its family, it is quite lively, has a similar flight, moves sideways up and down the branches, and hangs from the ends of the twigs in its search for insects. Mr. Audubon also states that the liveliness of the notes of this Warbler renders it conspicuous in the forests, the skirts of which it frequents. Its song, though neither loud nor of long continuance, he speaks of as extremely sweet and mellow. He found it as numerous in the State of Louisiana as any other Warbler, so that he could sometimes obtain five or six in a single walk.