THREE-TOED WOODPECKER. Picus tridactylus, Linn. Apternus tridactylus, Swazns. Le Pic tridactyle. Mr. Swarnson has applied the generic term Apternus to this Three-toed Woodpecker; and we refer the reader to the second volume of the North American Zoology, page 301, for a full explanation of the views of the scientific author in his systematic arrangement of this most extensive and characteristic family. The principal distinguishing feature of this genus is the absence of the hind-toe; a deficiency, however, which does not occasion any very material difference in the habits of the bird before us, which bear a close resemblance to those of the typical group. The present species is by no means uncommon in the northern parts of the European Continent, the vast forests of the mountainous parts of Norway, Sweden, Russia and Siberia, forming its principal habitat ; it is also found among the Alps of Switzerland, is but an accidental visitor in France and Germany, and has never been taken, we believe, in the British Islands. It subsists, like most of the Woodpeckers, on insects and their larvae, as well as fruits and various wild berries. It chooses holes in trees for its breeding place, which if too small it readily enlarges, the female laying four or five eggs of a pure white. The male and female present the usual differences of colour which characterize the family. In the male, the forehead is variegated with black and white; the top of the head is golden yellow ; the occiput and cheeks glossy black ; from the base of the bill a black stripe extends to the chest, between which and the eye runs a bar of white ; a narrow white line also extends to the occiput from behind the eye ; throat and chest white ; back, sides and under parts barred with black and white, the bars of the under surface beng more regular though the black is less deep; wings brownish black, with white spots on the quill-feathers ; the four middle tail-feathers black, the rest alternately barred with black and white ; the upper part of the tarsi covered with feathers ; the superior mandible brown ; the inferior dirty white, as far as the point ; irides obscure blue. Length nine inches. In the female, the top of the head is of a glossy or silvery white, interspersed with fine black bars. The rest of the plumage the same as in the male. In very old males the yellow of the head is more bright, and the white of the under parts predominates, but never loses the black transverse bars. Our Plate represents a male and female of their natural size ; the generic name Apternus, Swains., being inadvertently omitted.