Variation is chiefly connected with the modifications that occur in the upper or lower, sometimes both, portions of the central band; the lower seems to be the first to disappear, then the upper passes through various stages of reduction until it becomes simply a spot or dot about the centre of the wing. Specimens are occasionally found or reared, in which every trace of the band has departed from one or both fore wings. The greenish outer border of the wings is inwardly margined with darker, well defined and band-like in some examples, but less clearly marked, or even absent, in others. Near the base of the fore wings are often two dusky greenish cross lines. The hind wings, generally pretty much of the same ground colour as the fore wings, have a dusky band-like shade of variable width on the outer third; sometimes these wings are entirely dusky, approaching blackish. Very rarely specimens are bred in which there is no trace of green colour. Such an example was reared by Mr. Frohawk in April, 1882, from a caterpillar he found in Surrey. In this aberration all the markings (normally green) are light burnt-sienna red, the usual whitish blotch at the tip of the fore wings is pink; ground colour also pink, slightly tinged with grey in places. So variable is this moth in colour and markings, that in some collections at least one cabinet drawer is given to it so that the range of aberration may be adequately shown. Already about eighteen colour modifications have been named, and at least eight band variations have also received names. The egg is similar in general appearance to that of the next species (see Plate 4). Dr. Chapman states that it is more densely covered with an indiarubber-like gum, and this may cause it to seem darker than the eggs of the Eyed and the Poplar Hawk-moths. The eggs are laid singly or in pairs on the underside of elm or lime leaves. [Illustration] Pl. 2. LIME HAWK-MOTH. _Caterpillar and chrysalis._ [Illustration] Pl. 3. LIME HAWK-MOTH. {19} The figure of a nearly full-grown caterpillar (Plate 2) is from a drawing in colour by Mr. A. Sich. Shortly, the caterpillar may be described as green, roughened with yellow points, and with seven yellow oblique stripes on the sides, each edged above with purplish and reddish; the spiracles are ringed with reddish, and the curved horn is blue, inclining to yellowish beneath and at the tip; the roughened shield on the last ring of the body is reddish, marked with yellow. Head triangular, smoother than the body. Quite in its infancy, the caterpillar is a long, thin creature; the horn, which is divided at the tip, is covered with short, stiff hairs, and appears blackish; later on the horn becomes reddish, and the side stripes appear on the body. Although alder, birch, and several other shrubs and trees have been mentioned, there is no doubt that the foliage of elm and lime is the chief food of the caterpillar in a state of nature. Found in July and August.