Whitish or pale grey specimens, with black belly and jet black dorsal markings (Plate XII.), are males. Brown and brick-red specimens, with the markings of a more or less dark brown or red, are females. There are also brown, reddish-brown or olive males with the markings of a deep black, and grey males with brown markings. A very pretty colour variety, which affects only females, is olive with brick-red band and spots. Some males, just before exuviation, have the lower surface of a pale greyish-blue (_Coluber cæruleus_, Sheppard), with the outer ends of the shields black. Specimens with yellowish-white chin and throat, which may be tinged with red, are females; males have the throat black, or whitish with the scales spotted or edged with black. Exceptional females occur (in Carniola) which in this respect resemble the males. The markings vary considerably. Those on the back usually consist of a wavy or zigzag longitudinal band, flanked on each side with a series of spots corresponding to its sinuses; but this band may be partly or even entirely broken up into rhomboidal or transversely oval spots, or, losing its indentations, form a straight stripe edged on each side with a yellowish streak (as in some specimens of the var. _seoanei_, from North-Western Spain). The markings may be absent altogether (var. _concolor_, Jan), or reduced to a narrow straight vertebral band (_Pelias dorsalis_, Gray). In the var. _seoanei_ the zigzag band is often replaced by a dark brown vertebral band, three to five scales wide, bordered on each side by a series of subtriangular or crescentic black spots opposite to each other, as in the Pyrenean specimens of _V. aspis_. A pair of elongate dark markings are usually present on the back of the head, affecting the following shapes: |\,)(,)(,)(; By uniting together, this pair of markings may form a [V] or an X. An oblique dark streak extends on each side from the eye to the last labial shields, being sometimes prolonged a short way down the neck. The snout and vertex may be uniform or bear some symmetrical dark spots, or in some males be entirely black, the black involving the apex of the [V]-shaped marking. The labial shields are whitish or yellowish, those at least which are anterior to the eye being more or less broadly edged with brown or black. The belly and the lower surface of the tail vary from grey or brown to bluish, blackish-grey, or black, the sides usually dotted or spotted with whitish; sometimes, especially in females, the belly is dark grey, each shield with a white posterior border which is broken up by a series of small roundish black spots. The end of the tail is often yellowish, bright yellow, or pale orange below, rarely coral red, more commonly in females than in males. The iris is usually coppery red, more rarely golden suffused with brown.