CHAP. CIV.

UETULA'cEAS. BETULA.

1703

Russia, where whole tracts of forests of different kinds of trees occur, thereis scarcely any tree more frequently struck by lightning than the birch ; which,he says, refutes the superstitious notion of the Laplanders, who, believingthat the tree is never struck by lightning, seek for shelter under its branchesin a thunder-storm. It has constantly been observed, he says, that the birchis always struck by the electric fluid transervely, below the top, and shiveredto pieces; while the pine is ploughed by a deep furrow from the apex to theground, tearing off the bark, and leaving the tree entire. The common birch,Mr. Westwood observes, is a tree upon which a very great number of insectsfeed, seldom, however, causing any mischief of importance. Of these, it will besufficient to notice a few of the more remarkable; indicating by a star thosewhich not only feed on the birch, but on various other trees; and by a daggerthose which feed on the birch only; commencing with the Lepidoptera, thecaterpillars of which, either exclusively or partially, subsist upon its leaves.Amongst the butterflies, the Camberwell beauty (Vanessa Antiopa) is apartial birch-feeder, whilst the brown hair-streak butterfly (Thecla betulae)seems to be confined to birch woods ; appearing in the winged state in themonth of August. Amongst the Sphingate, Smerlnthus tiliae (the lime hawkmoth) occasionally feeds upon the birch. Amongst the Linnaean Bombyces,the singular lobster caterpillar (Stauropus fagi) partially feeds upon this tree,and is met with, though but rarely, at Birch Wood, in Kent. * Leioeampadictae'a and * L. dictaeoides, * Lophdpteryx camelina, *L. carmelita, * Ptilo-phora variegata, * E'ndroinis versicolor (the rare glory of Kent moth), thereputed British species *Aglaia tau, *Eriogaster lanestris, *Callimorphaminiata, * Lithosia quadra. Amongst the Woctuidse, * Apatela /eporina,♦Acronycta auricoma, f Ceropacha fluctuosa, *C. flavicomis (the caterpillarof which is a leaf-roller), *C6smia trapetzina, f C. fulvago, *Brepha notha,

* Catociila fraxini. Amongst the Geoinetridte, * Hybernia capreolaria,

* H. prosapiaria, * IT. defoliaria, # Phigalia pilosaria, * Bistore prodromarius,

* B. betuliirius, * Hipparchus papilionarius, + Cabera exanthemata, f Mela-

nippe hastata, f Emmelesia heparata. Amongst the smaller moths, fPla-typteryx Zacertula, * Drepana falcataria, * D. unguicula, * Pyralis barbalis,f Antithesia betuletana, f Anacampsis betulea, TEgeria «phecifdnnis (one ofthe small clear-winged hawk moths), and Zeuzera ae'seuli {Jig- 636. in p. 887.),feed upon the wood of the birch. The coleopterous insects, Balaninusbetulae, Deporaus betulae, Rhynchites betulae, and Chrysomela betulae, alsofeed upon the birch in the larva state, and are found upon it when they haveattained their imago form, devouring the tender leaves and young shoots.Several species of Tenthredinidae, or saw flies, also feed upon the leaveswhilst larvae, including Selandria betuleti, and Lyda betulae. The little flathemipterous insect A'radus betulae resides beneath 1553

the bark, whilst A'phis betulae, C6ccus betulae, andPsylla betulae subsist upon the young shoots andbuds. When the birch begins to decay, various fungiroot themselves into its wood. The principal of theseare Daedalea Aetulina Fries (^Igaricus Aetulinus L.,and our Jig. 1553.), Polyporus Aetulinus Fries (Boletus ietulinus Bull. t. 312.),and P. versicolor Fr. (our Jig. 1554.); of these, P. ietulinus generally growson the trunks of dead trees, and has white flesh, which has an acid tasteand smell. The epidermis is very thin and delicate, and easily 1554peels off; when dry the whole plant is very light, and its tex-ture is between coriaceous and corky. {Eng. FI ., v. p. 140.)

Polyporus fomentarius (see Q. Robur) and P. nigricans Friesare also found on the birch. The latter, though called theblack amadou, is quite unfit for making tinder. It is a verydistinct species, and is of a bright shining black, though, whenold, the epidermis becomes cracked, and of a dull ash colour.

Radulum orbiculare Fr. EL, 1. p. 149. (//ydnum radula FriesSyst. Mus., I. p. 423.; II. spathulatum Grev. FI. Edin., p. 406.) is found onthe trunks of dead birches. Phlebia radiata Fries grows on the living birch