_Reproduction._--In Herzegovina pairing takes place from the middle of June to the middle of July, and the eggs are laid soon after, to hatch in September or beginning of October. The eggs number six to sixteen, and measure 2 inches by 1-1/3 inches. The young measure 8 to 14 inches at birth. 10. COLUBER DIONE, Pallas The Dione Snake _Form._--Similar to the preceding. Head more convex, a little narrower; snout obtuse, scarcely prominent. Tail about one-fifth of the total length. _Head-Shields._--Rostral broader than deep, just visible from above. Frontal once and one-fourth to once and a half as long as broad, as long as its distance from the end of the snout, shorter than the parietals. Loreal as long as deep, or a little longer than deep. A large preocular, with a subocular below it, the latter very exceptionally absent; two or three postoculars. Temporals 2 + 3 or 3 + 3. Upper labials eight or nine (very rarely seven), fourth and fifth or fifth and sixth entering the eye. Four or five lower labials in contact with the anterior chin-shields, which are nearly as long as the posterior. _Scales_ smooth or faintly keeled, with two apical pits, in twenty-five or twenty-seven (rarely twenty-three) rows. Ventral shields not or but very obtusely angulate laterally, 172 to 214; anal divided; subcaudals 50 to 80. [Illustration: FIG. 23 (after Sordelli)] _Coloration._--Pale brown or greyish-olive above, with blackish cross-lines or dark brown or reddish, black-edged spots, and usually two or three more or less distinct pale longitudinal bands; two dark longitudinal stripes on the nape, usually united on the head and terminating on the frontal shield; a curved dark cross-band from eye to eye, and another, oblique, from the eye to the angle of the mouth. Lower parts yellowish, usually dotted or spotted with blackish. _Size._--Seldom exceeds a length of 3 feet. The largest specimen examined by me measures 37 inches. _Distribution._--Across temperate Asia from Asia Minor, Transcaucasia, and the southern border of the Caspian Sea, to the Amur, Corea, and China. In Europe the habitat of this snake is restricted to the steppes of Southern Russia, between the Caucasus and the Lower Ural. The specimen figured on Plate VI. is from Sarepta, on the Volga. _Habits._--This snake frequents arid, sandy localities, and is only exceptionally found in small woods. Nothing more is known of its habits. 11. COLUBER LONGISSIMUS, Laurenti (_Coluber æsculapii_, Lacepède; _C. flavescens_, Gmelin) The Æsculapian Snake _Form._--Slender. Snout obtuse, scarcely prominent; head narrow. Tail about one-fifth to one-fourth of the total length. [Illustration: FIG. 24]