_Distribution._--_Vipera berus_ ranges over the whole of Northern Europe, to the extreme north of Scotland, and the sixty-seventh degree in Scandinavia, and right across Northern Asia as far east as the island of Saghalien. It is generally distributed in Great Britain, occurring also on the Isles of Arran, Islay, Skye, Lewis, and Mull, rare or absent in some districts, common in others. Its distribution in Central and Southern Europe is irregular. In Western France it does not extend much beyond the Loire to the south, only isolated captures being on record from the departments Vendée, Deux-Sèvres, Vienne, and Indre. Of rare occurrence south of Paris, in the departments Yonne and Allier and in the mountains of Auvergne, it is again abundant in some parts of the Central Plateau. To the east it is recorded from the departments Aude, Haute-Marne, and Vosges. In Belgium, it is known from Flanders, Limburg, the Meuse Valley, and the Ardennes; in Holland it is pretty generally distributed in the uncultivated parts. It is spread over nearly the whole of the German Empire with the exception of the vine districts, where it is absent or extremely rare; it is also very scarce in the mountains of the Black Forest; it is on record from only a few localities in Lorraine, and has never been found in Alsatia. In South Germany it is rarely found below 1,000 feet altitude. In Switzerland it is absent from the Jura, but occurs in the Alps chiefly between 2,500 and 9,000 feet. To the East it extends to Russia, as far north as 64°, Austria-Hungary, confined to the hills in the south, and Roumania. In the Balkan Peninsula it occurs in the mountains of Bosnia, of Herzegovina, and of Bulgaria, up to 7,000 feet. Absent from the South of France, it curiously reappears in the hills of the north coast of Spain, even at sea-level in Galicia, and in a few localities in North Portugal. On the southern side of the Alps it is much rarer than _V. aspis_, but it has established itself in a few low-lying districts in Lombardy, Venetia, and the neighbouring part of Emilia.