CHAP. CV.

CORYLA'cEiE. euE'llCUS.

1819

small solitary leaf-rollers (Zlirtrix viridana Haworth): for one of this sortseldom consumes more than four or five leaves, if so much, during its exist-ence. The number, therefore, of these caterpillars must have been almostbeyond conception; and that of the moths, the previous year, must also havebeen very great; for the mother moth only lays from.SO to 100 eggs, whichare glued to an oak branch, and remain during the winter. It is remarkable,that, in this wood, during the two following summers, these caterpillars did notabound.” ( Insect Transform., p. 203.) The moth (c) varies in the expansion ofits wings from 7 to 13 lines: the anterior wings are pale green, with a whitishmargin in front; and the posterior wings brownish. It is so extremely abun-dant, that, towards the end of the month of June, when it first appears, itmay be shaken from the trees in perfect showers. The caterpillar (a) of thismoth rolls up the oak leaves in a very ingenious manner, so as to form a verycommodious retreat; in which, indeed, it ordinarily resides, the centre of theroll being open: its diameter is proportionable to that of the body of theinsect; and the roll is secured by various little packets of silk attached to thebody of the leaf, and to the adjoining part of the roll, as represented infig. 1647. at b. Rdaumur, in the second volume of his Memdres, has given avery detailed account of the manoeuvres employed by the caterpillars in theconstruction of these leafy rolls. These caterpillars were so numerous inKensington Gardens in May and June, 1832, that “the excrementitious matterfrom them kept falling and tinkling on the grass below, so frequently as togive the idea of a sprinkling of rain being then falling.” (Mag. Nat. Hist., v.p. 671.) Millions of small lead-coloured caterpillars, tinted with green, andslightly hairy, were then some of them half an inch long, and depending onthreads stretching to the length of 7 ft. or 8 ft. In some cases, a colony offifty or a hundred of these insects appears to set off all at once from some pointin a branch, and each to make the best of his way to the earth, the threadsdiverging into numerous different lengths, apparently according to the age andvigour of the caterpillar. At Haslemere, in 1830, 1831, and 1832, the ravagescommitted by this insect were so great, that whole woods of oaks were strippedof their leaves, and looked as if blighted by lightning. Each tree was “ coveredwith the remains of skeleton leaves, curled up, and surrounded with a filmyweb: its trunk and branches had a misty appearance, as if enveloped in whitegauze; while here and there hung suspended a long web, or a caterpillar thathad not yet found a habitation for itself in which to undergo its final change.”(Ibid., p. 670.) This insect is the same as that noticed in Brown’s editionoi White's Seiborne, p. 311., in a note of the late Mr. Markwick. In theGardener’s Magazine for 1829 (vol. v. p. 610.), a writer, describing the ravagesof this insect on the oak woods in Wales , says the coppices appeared to beall alive with them, so immense were the masses they formed. These insects,notwithstanding their numbers, appear, in their moth state, to have manyenemies. White says that he saw a flight of swifts busily employed in“ hawking them and, in the Magazine of Natural History (vol. v. p. 670.), itis stated that the Jf'mpis llvida, an insect of something less than their own size,fixes on them, “ something in the manner that a stoat would on a hare or rab-bit,” and flies about with its victim, but never lets it go till it has destroyed it.

Amongst the Butterflies, Thecla quercus, or the purple hair-streak, is theonly species which feeds upon the oak in the larva state: its caterpillar issmall, and bears considerable resemblance to a woodlouse, being one of theonisciform larvae. One which M. Lyonnet (Recherch. sur VAnat., 8>c., de differ.Especet d’lnsectes, 2 me part. pi. 36.) reared ceased to eat on the 1st of June;'t then assumed a rounded form, and in three days arrived at the chrysalisstate, without spinning any cocoon; and on the 27th of the same monththe butterfly appeared. In its final state, it is an active elegant insect,sporting about the highest twigs of the oak. It is about 1| in. in theexpansion of the wings, which are of a bluish black on the upper side in themales; but in the females they are black, with a rich glossy blue disk. Owingt0 their smaller size, and more brilliant colouring, the females have been by