Pinellia
(a commemorative name, given to this genus by Tenore). SYNS. Atherurus, Hemicarpurus. ORD. Aroideae (Araceae). A genus comprising three or four species of hardy, tuberous herbs, natives of North China and Japan. Flowers all fertile; spathe marcescent, the tube convolute, the blade oblong and concave; spadix naked at base, the appendix worm-like, elongated, exserted; peduncle solitary. Leaves tri-or pedati-sect, membranous; segments oblong-lanceolate or elliptic, acute; petioles elongated, sometimes bearing gum at apex. The species described below thrives in any sandy, well-drained border. It is readily propagated by division during winter, or at any time before growth has too far advanced.
P. tuberifera (tube-bearing). fl., spathe with a narrow-cylindrical tube and an oblong lamina; spadix with a filiform appendage, twice as long as the lamina of the spathe. l., adults trisected; segments oblong-elliptic, acute at both ends, the middle one nearly or quite twice the size of the lateral ones; petioles bearing tubercles. Japan, &c.
PINE SAWFLIES. Under Lophyrus and Lyda will be found some general remarks on the Sawflies that belong to these genera. The species are all more or less hurtful to Conifers, but Lophyrus Pini is the one generally denoted by the name of Pine Sawfly. The insects are heavy-bodied, with four transparent wings, which often show a play of iridescent colours. In the male they reach about 1/2 in., and in the female about 3/4 in., in their expanse. The male is black. The female is pale yellowish-white, with black head, antennae, and breast; and the back between the wings, and a large patch on the abdomen, are black. The eggs are laid on the leaves, in slits made by the females. The larvae feed in company, eating the leaves from the tips downwards, and also gnawing the bark of the young twigs, and thus doing great damage to the Scotch Fir. They are usually light greenish-yellow in colour, more rarely pale yellow, or dark green above, and are sprinkled with minute black granules. The head is brown, with dark spots. When full-fed, the larvae crawl under moss and leaves, or into crevices, and spin oval cocoons, about 1/2 in. long, of very compact texture, and usually dull brown in colour.
The other Sawflies most injurious to Firs and to other Conifers in Britain, are the following: Lophyrus frutetorum, L. sertiferus (L. rufa), and L. virens; and of the genus Lyda the most hurtful are L. erythrocephatus, L. nemorum, and L. stellatus. In their general appearance and habits, they agree with Lophyrus Pini, differing only in minor details. It is unnecessary to enter into descriptions of the different species, since they are so much alike; the same means of destruction may be employed against all of them. Remedies. Moss, loose bark, and other debris, amongst which the cocoons are spun, should be collected and burned. The larvae may be hand-picked from the branches, or crushed on them, with good results. Naphtha and solutions of Hellebore have also been directed upon them successfully. They may be shaken from larger trees, and crushed under foot; or they may be prevented from re-ascending by putting a belt of any sticky compound round the stems of the trees.
PINE WEEVILS. Hylobius Abietis is a beetle very hurtful to the Scotch Fir, and to various other Conifers, as it feeds, in the perfect state, on the bark of the young shoots. It is seldom very destructive in gardens, or in pleasure-grounds, but does most harm amongst young trees growing in the neighbourhood of recently-felled plantations, where brushwood, &c., has been lying about for some time. The beetles are 1/2 in. to 3/4 in. long, dull black, with scattered tufts of yellow hairs. The thorax is narrowed in front, and the head is small, and bears a decurved proboscis, on which are the antennae, abruptly elbowed at the tip of the long first or basal joint. The wing-cases are rough, with lines of pits and tubercles, and there are numerous small pits on the head. The beetles appear from May to July. They gnaw the buds and the bark of the twigs, interfering, in this way, with the development of the trees. The eggs are laid in crevices on stumps of Firs, on logs, and on cut branches; and the white, legless larvae, on hatching, burrow into the wood, and feed on it, making galleries that increase in size with their own growth. At the end of the burrow, a cocoon is formed, by the full-fed larva, of the fragments gnawed by it in making the gallery. Here, in spring, it becomes a pupa, in which state it passes about four weeks. Pissodes notatus and P. Pini belong to a genus closely allied to Hylobius, and are not less hurtful. They are, however, easily known from that genus by having the antennae in the middle of the narrowed beak, while Hylobius has them situated quite near its tip. The thorax also is broader compared with the wing-cases. Both species of Pissodes are rather smaller than Hylobius Abietis. In general appearance and colour, they agree not a little with that beetle. They are of a pitchy-brown colour, but this is modified by a coating of yellowish-white scales or hairs, more conspicuous in certain parts. Their general appearance is shown Both are about 1/3 in. long. The larvae of P. notatus live under the bark of living trees of good size; and those of P. Pini in old stumps, &c., making winding galleries, in which, when full-fed, they spin oval cocoons of fragments of wood and silk. The beetles emerge from July to September. As beetles, they destroy the young branches of Conifers by boring small holes in them, and sucking the sap Resin is apt to flow out from the openings, and the branches die, and fall off.