Fig. 20.
Caterpillar of Puss Moth.
The reddish brown chrysalis is enclosed in a hard cocoon spun up and securely attached to the trunk or under a limb of the tree upon which the caterpillar was nourished, or upon some other adjacent thereto. I once found a cocoon on the lower rail of a garden fence. In constructing the cocoon fragments of bark and wood are worked on the exterior, but failing these the caterpillar will make use of any available material for the purpose. If enclosed in a tumbler covered with glass it will spin a transparent cocoon. Emergence from its strong pupal chamber would appear to be a difficult matter, but the caterpillar and the chrysalis both contribute something towards assisting the final efforts of the moth to escape. The caterpillar, in constructing the cocoon, is careful to make the exit end with a thinner layer than the other parts; then the chrysalis is provided with a cutting implement in the shape of a keel-like arrangement on the fore part, and with this it operates at the right time on the weak end until a breach is made; the moth breaks the head end of the chrysalis case and moistens
the ruptured material with a softening fluid so that the insect is able to force its way out of the cocoon; the chrysalis case remains in the cocoon.
The moth is on the wing in May and June, and sometimes July. Three specimens that I reared this year (1907) from eggs found on a leaf of poplar last year, emerged on June 4th, 10th, and July 12th. They all pupated about the same time, and side by side on cork bark.
I believe this species has not been recorded from the Orkneys or the Shetlands, but with these exceptions it seems to occur in more or less frequency throughout the United Kingdom. It is widely distributed in Europe, and its range extends to Siberia. In Lapland, Amurland, Japan, and North Africa it is represented by named forms.
The Lobster (Stauropus fagi).
The English name of this insect does not apply to the greyish brown or sometimes blackish moth (Plate [26]), but to its remarkable caterpillar, the figures of which, on Plate [27], are reproduced from drawings by Mr. Alfred Sich. In colour this curious-shaped creature is always some shade of brown, the head is marked in front with reddish, the ring divisions of the body are darker brown, and the hind rings are reddish brown.
The late Mr. W. H. Tugwell, referring to the early history of these caterpillars, states that a female of the blackish form received from Reading in May was kept alive for seven days, during which time she laid a few eggs on oak leaves each night; "all told" she produced forty eggs. As she was then quite exhausted, a good many had probably been laid previously. The eggs when first laid are of a pale cream colour, hemispherical in shape and flattened beneath. About the seventh day a circular depression, and a dark spot, appear, and gradually the entire egg assumes a dull purplish colour. "On the tenth day the caterpillars hatch out. When they first leave the shell they appear extremely large, this is partly on account of the long legs and the caudal appendages which are ever nervously twisting about. The young caterpillars most carefully keep guard over their own egg-shell, which is to them an all-important item, as this provides them with their first meal—the first and only food they take for seven days, in fact, for a longer period, as it is not until after moulting their first skin that they eat any other food. This fact I proved over and over again, as, being an invalid, my time was quite free to watch them hour after hour and day after day. As soon as they have eaten their way out of the shell they stretch themselves, and then from time to time nibble portions of the white chitinous-looking egg-shell, and a tough morsel it seems to be for them; but they never leave it for more than an inch or so, and then rapidly come back. They keep nervously moving around and about this, and if perchance another caterpillar should approach within touch of it, a vigorous attack is made to drive off the intruder. All going well during the first hour or two, the whole of the shell, or sometimes not more than from half to two-thirds of it is consumed; and once the caterpillars really leave the egg-shell, that is, walk away from it, they do not touch it after. If by any chance a young caterpillar gets driven away from the egg-shell, death is certain to result, as I could never induce them to feed on portions of empty shells left by others; nor would they eat the leaves or the brown stipules of the beech, which it has been suggested they do eat. In no single instance did they eat other food in their first skin save and alone the one meal of their own egg-shells."