Tenaris
(said to be the native name in South Africa). ORD. Asclepiadeae. A small genus (two species) of greenhouse, erect, slender, nearly simple, perennial herbs, natives of South Africa. Flowers pink or whitish, cymose; calyx deeply five-cleft, the lobes acute; corolla tube shortly campanulate, the lobes five, long, linear-spathulate; coronal scales ten, affixed to the new staminal tube; stamens affixed at the base of the corolla, the filaments connate in a short tube. Leaves opposite, narrow-linear. Only one of the species has been introduced. For culture, see Ceropegia. T. rostrata (beaked). fl., corolla whitish, densely covered towards the base with minute, purple dots, 3/4in. in diameter, rotate; outer corona of five small, yellowish lobes; inner one of five pinkish segments; peduncles one (or two ?) flowered, three to five lines long. l. about four pairs, distant, linear, acute, 2in. to 3in. long, 1/8in. broad, arched. Stem 1 1/2ft. high, slender. East tropical Africa, 1885.
TENTHREDINIDAE, or SAWFLIES. A family of Hymenoptera (which see), of very great interest to gardeners, because of the damage the insects do to various cultivated trees, shrubs, and herbs. The name Sawfly refers to the most characteristic feature of the family, viz., the existence in the female of an organ, very like a minute double saw, at the hinder end of the body. The saw is a modified ovipositor, and is made up of two blades, each of which consists of a support along the back, and of the cutting portion, or saws strictly so called, secured to it along one side. The two saws are quite like one another. In each the edge is toothed, and has cross-bars, which are often furnished with minute teeth, and thus it combines the action of a saw with that of a file. The toothing and bars of the saws differ in the various species of Sawflies. They are protected, when not in use, in a two-jointed sheath. Sawflies, for the most part, have moderately broad bodies, with the abdomen united to the thorax by its full width; differing in this from most Hymenoptera, which have the abdomen fixed to the thorax by a slender stalk. The head is always broader than long, but is not broader than the thorax. Eriocampa limacina represents the majority of the group in form and general appearance. The body is usually smooth, sometimes hairy, and seldom marked with punctures. The colour is generally black or some dark shade, often with a metallic lustre; sometimes, it is coppery-green, blue, pure green, yellow, or red. The legs are often rusty-red, even when the body is some other colour; they are of fair size in proportion to the body, and have all their parts well developed. Each bears two sharp spurs near the tip of the tibia. The wings are of much the same structure as in other Hymenoptera; but the venation is characteristic in so far that one of the cells near the hind margin of each front wing, known as the "lanceolate cell" (lc, Fig. 12) is found in no other Hymenoptera. Generally, the wings are transparent, and more or less iridescent. The parts of the mouth are fitted for cutting vegetable structures. There is usually a little difference in aspect between the sexes, due to slight modifications of the limbs, the body, and the organs of the head.
Sawflies abound from May till the end of July; and of some species a second brood appears in autumn. The mature insects are of sluggish habits, and, in dull weather, sit on the herbage, without change of position, for hours at a time. A few species are comparatively active, especially in bright weather. Sawflies frequent flowers, both to obtain honey or pollen, and to feed on the minute insects that are there found. They are partial to shallow, open flowers, e.g., Buttercups and Umbelliferae. The larvae live on plants. The eggs are laid on leaves, frequently along the lower surface of the veins, or on twigs. In either case, the mother makes a slit for each egg with her saws. Many Sawflies have been found to be parthenogenetic, the females producing fertile eggs without the aid of the males, which, indeed, in some species are still unknown.
The habits of the larvae vary greatly. Most of them feed exposed on the surface or edge of a leaf, some species in groups, others singly. Some (Lyda) spin silken webs, in which many live, each larva in its own tube, sheltered in the common web. A few live in leaves rolled or folded by themselves to afford them protection. Others bore into twigs. Some are leaf-miners, and others burrow into fruits. A considerable number of species make galls in stems or leaves; many of the gall-makers abound on Willows. The forms of the larvae vary with their modes of life; but by far the most species have a cylindrical body. A very common position, when at rest or feeding, is to have the front half of the body straight, and the hinder segments rolled spirally inwards. In general appearance, the larvae closely resemble those of many Night Moths, or Noctuae, having, like these, three pairs of true legs, and several pairs of prolegs; but they differ in the number of the latter, often having from six to eight pairs, instead of five pairs, as in Noctuae, and the fifth segment always bears prolegs (if any exist) in Sawfly larvae, but never in the larvae of the Noctuae. Sawfly larvae are protected by their inconspicuous form and colour, or by dropping to the ground, if danger threatens, or by disagreeable excretions on the surface of the body. Some, e.g., Slug-worms, excrete slimy substances, others bear a flaky coating, &c. Brightly-coloured kinds are mostly protected by disagreeable excretions. Most of them pupate in silken or earthen cocoons, under soil, in crevices, or in other sheltered places. The more injurious species of Sawflies, and the remedies most effectual against each, will be found discussed at greater length under the following heads: Gooseberry and Currant Sawfly, Lophyrus, Lyda, Nematus, Pine Sawflies, Slugworms, and Turnip Sawfly.