The caterpillars of two of our largest and handsomest butterflies, the painted lady (_Cynthia cardui_, Stephens), and the admiral, or _Alderman_ of the London fly-fanciers (_Vanessa atalanta_), are also leaf-rollers. The first selects the leaves of the great spear-thistle, and sometimes those of the stemless or star-thistle, which might be supposed rather difficult to bend; but the caterpillar is four times as large and strong as those which we have been hitherto describing. In some seasons it is plentiful; in others it is rarely to be met with: but the admiral is seldom scarce in any part of the country; and by examining the leaves of nettles which appear folded edge to edge, in July and August, the caterpillar may be readily found. Another butterfly (_Hesperia malvæ_) is met with on dry banks where mallows grow, in May, or even earlier, and also in August, but is not indigenous. The caterpillar, which is grey, with a black head, and four sulphur-coloured spots on the neck, folds around it the leaves of the mallow, upon which it feeds. There is nothing, however, peculiarly different in its proceedings from those above described; but the care with which it selects and rolls up one of the smaller leaves, when it is about to be transformed into a chrysalis, is worthy of remark; it joins it, indeed, so completely round and round, that it has somewhat the resemblance of an egg. Within this green cell it lies secure, till the time arrives when it is ready to burst its cerements, and trust to the quickness of its wings for protection against its enemies. Among the nests of caterpillars which roll up parcels of leaves, we know none so well contrived as those which are found upon willows and a species of osier. The long and narrow leaves of these plants are naturally adapted to be adjusted parallel to each other; for this is the direction which they have at the end of each stalk, when they are not entirely developed. One kind of small smooth caterpillar (_Tortrix chlorana_), with sixteen feet, the under part of which is brown, and streaked with white, fastens these leaves together, and makes them up into parcels. There is nothing particularly striking in the mechanical manner in which it constructs them. It does precisely what we should do in a similar case: it winds a thread round those leaves which must be kept together, from a little above their termination to a very short distance from their extreme point; and as it finds the leaves almost constantly lying near each other, it has little difficulty in bringing them together, as is shown in the following cut, _a_. The prettiest of these parcels are those which are made upon a kind of osier, the borders of whose leaves sometimes form columnar bundles before they become developed. A section of these leaves has the appearance of filigree-work (see _b_). [Illustration: Nest of Willow-leaf Roller.]