The lower parts vary as much as the upper: sometimes black or steel blue, with or without whitish or reddish dots or spots, sometimes yellowish or pale reddish, with brown dots or marblings; in some young, white with greyish dots. The throat is yellowish white or pale reddish, uniform or speckled with blackish, sometimes (males) nearly entirely black. The end of the tail is usually bright yellow or reddish, or at least with a few bright spots. And finally we must mention black specimens—some nearly black by darkening of the ground colour, others intensely black by enlargement of the markings. A specimen from Piedmont, in the Turin Museum, shows the ground colour reduced to mere narrow light bars disposed in pairs. In most of these black specimens the chin and throat remain entirely or partially yellowish or reddish, and a few spots of the same colour are to be seen under the end of the tail.
A remarkable form of V. aspis, which some herpetologists would perhaps regard as entitled to rank as a species, is the var. hugyi, Schinz, from Calabria and Sicily. It is in some respects intermediate between V. aspis and V. latastii. The snout is rather more pointed than usual in the typical form, often, though not constantly, more strongly turned up at the end, and the canthus rostralis may be distinctly raised. Constantly two canthal shields, the second in contact with the supraocular. Ventral shields 134 to 148; subcaudals 30 to 43. Pale greyish, yellowish, brownish, or reddish, above, with a broad wavy dark brown vertebral band, edged with darker; this band sometimes broken up into transversely oval spots; a lateral series of blackish-brown spots, each corresponding to the sinus of the dorsal band.
Specimens so completely intermediate between Vipera aspis and V. berus as to render their naming arbitrary are known from parts of France and Italy where the two species coexist, and are probably to be regarded as hybrids.
Size.—The largest specimen examined (St. Sever, Landes, in the Lataste Collection) measures 2 feet 21⁄2 inches. It is a male. The largest female in the British Museum is 2 inches shorter.
Distribution.—Vipera aspis is found over the whole of France south of a line connecting the departments Loire-Inférieure, Orne, Seine-et-Marne, and Meurthe-et-Moselle, and ascends the Pyrenees to the altitude of 7,250 feet. In Germany it is known from Lorraine and the Black Forest, in Switzerland from the western and southern parts, up to 5,000 feet on the northern side of the Alps. It occurs also in Austria, in the Southern Tyrol and in the Karst, and is distributed over the whole of Italy and Sicily, reaching an altitude of 9,700 feet in the Alps. Most of the specimens from the western parts of the Balkan Peninsula which have been referred to this species belong, apparently, to V. berus, var. bosniensis, but one from Jahorin in Bosnia, altitude 5,650 feet, preserved in the Bosnian Museum, is pronounced by Werner to be an unquestionable V. aspis.
Habits.—This Viper shows a predilection for hot and dry localities. It is both diurnal and nocturnal, and does not seem to wander far from its hole in a rock or in the earth. It is slow in its movements, but very irascible, and innumerable accidents, in some cases fatal to man, are caused yearly in many parts of France, where it is extremely abundant. Its food consists principally of small mammals, young birds, and lizards, but the very young eat insects and worms. In France it retires into its winter-quarters at the end of October or in November, and numerous specimens often congregate in the same hole; it resumes its activity towards the end of March or the beginning of April, sometimes as early as the end of February. In rare cases it will even leave its retreat in the middle of winter, to bask in the sun. In captivity it long retains its savage temper, and usually refuses all food.
Reproduction.—Vipera aspis pairs in April and May; the pair are entwined in each other’s coils. The young, four to eighteen in number, but rarely more than ten, are born in August or September, and measure 7 or 8 inches.
Several cases of dicephaly in young specimens have been described.
25. Vipera latastii, Bosca
Lataste’s Viper
Form.—Heavier than in the preceding. Head similar, but snout more pointed and loreal region slanting towards the lip, well visible when the head is viewed from above. The extent to which the snout is turned up at the end varies considerably, sometimes similar to certain specimens of V. aspis, sometimes forming an appendage which is only a little less developed than in V. ammodytes. Length of tail six and a half to seven and a half times in total length in males, seven and a half to nine times in females.