George Vernon Hudson

“ The female has all the wings of a relatively more attenuated shape; the fore-wings are green, mottled with black; the hind-wings are pale reddish-brown, shaded with green near the termen; the abdomen is also reddish-brown, becoming green at the extremity. The species is rather variable in both sexes. In the male the white spots on the fore-wings vary considerably in size, and there are occasionally several additional spots near the body. In the female the black markings of the fore-wings are sometimes much more extensive than the green ground colour. ”

“ Younger specimens differ in being of an olive-green colour, which is much more pronounced, when they are small. The last act performed by the caterpillar, prior to undergoing its transformation, is the construction of the above-described trap-door at the top of its burrow. This done the insect retreats to the bottom, its posterior segment resting on the termination of the vertical gallery. In the course of a few days the skin is cast off and worked downwards to the bottom of the burrow, underneath the last segment of the pupa. ”

“ As development progresses in the pupa it becomes darker in colour, especially on the wing-cases, where, in some female specimens, the future black markings of the moth are quite discernible as long as two months before emergence. Other specimens remain pale in colour until within a fortnight or three weeks of the appearance of the imago, when the green colouring of the wings suddenly becomes visible through their semi-transparent envelopes. ”

“ The lid itself is of a larger size than the orifice which it covers, and this makes it extremely difficult, if not impossible, to force it open from the exterior, especially as it always fits down very closely as long as the insect remains in its burrow. ”

“ As a consequence of this strengthening, the flight of the larger species is very powerful, and to this, combined with a choice of larval food, which is often rather indiscriminate, may perhaps be ascribed the wide range of the group, rather than to its antiquity. ”

“ The object of this contrivance is, no doubt, to prevent the ingress of enemies, large numbers of spiders, slugs, wood-lice, and various orthoptera being frequently found in both central and lateral tunnels, but they are quite unable to pass the trap-door. ”