This exceedingly lovely little Swallow, whose plumage reflects the radiance of the Humming-birds, is found, as I am informed by Mr. Hill, in the higher mountains formed by the limestone range of the very centre of the island, as in Manchester, and St. Ann’s. It is not until we ascend this central chain, that we meet with this sweet bird, occasionally in the more open dells, but principally confined to the singular little glens called cockpits. The description is from a dried specimen in my possession, kindly presented by Mr. Hill. GREAT BLUE SWALLOW.[17] _Progne Dominicensis._ _Hirundo Dominicensis_, +Linn.+ _Hirundo albiventris_, +Vieill.+ Ois. Am. pl. 28. [17] Length 8 inches, expanse 15¹⁄₄, flexure 5¹⁄₂, tail 2, rictus ¹⁹⁄₂₀, beak along culmen ⁵⁄₁₀, tarsus ¹³⁄₂₀, middle toe ¹³⁄₂₀, hind toe ⁵⁄₁₀, outer toe slighter longer than inner. Irides dark hazel. As closely allied to the Purple Martin, in manners, as in form and colouring, I long mistook the present bird for that well-known species, as I think others have done also. The white belly is, however, a sufficient mark of distinction. It is very common, at least in the lowlands and inferior mountain ranges, during the summer; some remain with us through the winter, but as there is a very marked diminution of their numbers, I conclude that a large body of them migrate on the approach of that season, probably to Central America. About the end of March we see them in great numbers, assembled early in the morning on the topmost branches of the lofty cotton trees, which at that season are leafless. On these they crowd so closely, side by side, that I have known five to be killed at one discharge. In the autumn we observe exactly the same habit. Perhaps we may trace some analogy here to those periodical congregations of other species which are known to be connected with migration. It is a remarkable fact, that of the seven species of Swallows and Swifts which summer in North America, all of which are stated to migrate to the southward before winter, not one should have occurred to me in Jamaica. Although every day through the winter months, my almost undivided attention was given to birds; and though from August to April about thirteen hundred specimens of birds fell into my hands, more than one thousand of which were shot by myself and my servants, not a single individual of a North American species was observed among them. I simply state the fact, leaving any one to draw his own inferences.