"Why is it called 'Martin'?" asked Rap. "Did somebody named Martin find it, as Mr. Wilson found the Thrush they named after him?" "No, my boy, the name comes from a Latin word, meaning 'warlike' or 'martial,' because in the Old World certain Swallows there called Martins were considered good fighters, and very brave in driving away Hawks and other cannibal birds. Don't you remember that Mars was the God of War in classic mythology, and haven't you heard soldiers complimented on their fine _martial_ appearance?" The Purple Martin Length seven and a half inches. Upper parts shining blue-black, not quite so glossy on the wings and forked tail. Under parts the same as the upper in the male, but grayish-white in the female and young ones. Song rich and musical, of two or three flute-like notes. Nest made of a few leaves or straws, in a bird-box when it is provided--otherwise in a hollow tree. Eggs white, without any spots. A good Summer Citizen and a favorite everywhere; but for many reasons it is growing scarcer every year. The English Sparrow is one of its greatest enemies, and not only drives it from its nesting-boxes, but attacks the young birds. A member of the guild of Sky Sweepers. [Illustration: Purple Martin 1. Male 2. Female] The Barn Swallow Length six to seven inches. Upper parts shining steel-blue, but the face buff. Under parts rich buff, brick-red on the throat, where there is also a steel-blue collar. Tail very long and deeply forked, with the side-feathers narrow, and some white spots on them. Song a musical laugh, heard when the birds fly low over meadows and ponds. Nest a sort of bracket, made of little mud balls and straw stuck on a beam in a hayloft. Eggs white, with plenty of reddish-brown spots. A Summer Citizen in most of the United States. A Sky Sweeper of the very first rank. [Illustration: Barn Swallow.] "Barney is a charming neighbor, who should be welcome in every home--sociable, musical, and very useful in destroying the flies and gnats that worry horses and cattle. Though it builds its first nest in May, it often brings out its last brood in August; thus during its long nesting season consuming a very large share of insects, and proving itself a kind friend to the cows at a time when flies are most persistent." The Tree Swallow. (Or WHITE-BELLIED SWALLOW) Length six inches. Upper parts sparkling green, with darker wings and tail, the latter but little forked. Under parts snow-white. A sweet, twittering song. Nests in the hollows of dead trees, usually in old Woodpeckers' holes, but occasionally in bird-boxes. Eggs pure white. [Illustration: Tree Swallow.] A good Citizen of the United States, but more shy than the Martin and Barn Swallow; these two often return, year after year, to some favorite nesting place, but the Tree Swallow is not so reliable. A Sky Sweeper. The Bank Swallow (Or SAND MARTIN) The smallest Swallow, only five inches long.