AN ENCYCLOPADIA 
OF HORTICULTURE. 21 
TETRANYCHUS TELARIUS, or RED 
SPIDER. This is not a Spider, but a true Mite, It 
is frequently most injurious to cultivated plants, and is 
peculiarly hurtful to certain fruit-trees (e.g., Plum), to 
Hollyhocks, and to many of the more delicate greenhouse 
plants. A good deal of doubt exists as to whether there 
is only one species of Red Spider, liable to variation in 
colour, and in other minor points, or whether there are 
several closely-related species. It matters little to gar- 
deners whether there are more than one or no, since the 
habits, harm done by them, and remedies against them, 
are the same for all, and will be discussed here as if 
there were but one. The creatures are too small to be 
seen with the unaided eye, save as minute, moving specks 
on the leaves; but often their numbers render the effects 
produced by them conspicuons. Their colour is usually 
some shade between rust-red and brick-red, but some 
(probably immature) are greenish, with brown specks on 
the sides. The body is oval, without any separation 
between the thorax and abdomen (unlike the structure 
in Spiders). There are four pairs of nearly equal legs, 
of which two pairs are turned forwards and two back- 
wards. On the upper part of the body, near the front, 
are two minute eyes, and a beak or sucker, for boring 
into, and sucking juices from, the leaves of plants. Near 
the hinder end of the body, on the lower surface, is a 
conical wart, which is an organ used for spinning threads. 
The name Spider has probably been given to these 
mites because of their powers of spinning. The females 
lay eggs; from these emerge larve, which differ from the 
adults in their size, and in haying only six legs. The 
mites, when they establish themselves upon plants, spin 
webs of very fine texture on the backs of the leaves. 
They then, by means of their suckers, bore into the 
leaf-cells and suck out the sap. The leaves become 
yellowish or greyish-green, marbled with paler patches 
on the upper surface; the glistening web covering 
the lower surface renders it grey. A severe attack by 
Red Spider kills the leaves, which fall prematurely; the 
fruit crop is lessened; and the young branches formed 
the next year are stunted and weakened. 
Prevention. Attacks of Red Spider are worst when 
the growth of plants is checked by drought and heat; 
hence, any measures that promote growth—such as fre- 
quent syringing—diminish the risk to some extent. 
Plants that show symptoms of being attacked, should 
be at once separated from the rest, and specially 
treated. Free access of air is much to be recommended. 
Soot, caustic lime, sand impregnated with spirits of tar, 
or other similar substances, may be laid round the bases 
of the stems of the plants to be protected, to prevent 
the mites from getting access to them. Poles and other 
Supports should have their surfaces planed quite smooth, 
to prevent the mites from harbouring in crevices, and 
to allow of being thoroughly washed. 
_ Remedies. Sulphur, in the form of Flowers of Sulphur, 
1s almost a certain cure for Red Spider, and for some 
Fungi. It is sometimes dusted dry on the leaves, but is 
better employed in solution, e.g., 1b. of sulphur, boiled 
with 2b. of quicklime in four gallons of water; or the 
sulphuret of lime may be employed, in the proportion 
of 4oz. of sulphuret to 202. of soft soap and one gallon 
of boiling water. The sulphuret and the soap should 
be thoroughly mixed, and must be well stirred 
while the water is being poured on them. The plants 
may be dipped into the mixture; and it may be applied 
to the bark with a stiff brush. Various other washes 
have been found useful; e.g., Gishurst Compound, 
Veitch’s Chelsea Blight Composition, and solutions pre- 
pared from quassia-wood. Fumigation with tobacco- 
Smoke, or with sulphur and chalk,,mixed in water and 
painted on the hot-water pipes, is also recommended. 
To cleanse infested walls, the following method may be 
employed with success: Add clay to a solution of soot 
Tetranychus telarius—continued. 
in water till the mixture is of the consistency of thick 
paint; then add lb. of flowers of sulphur, and 2oz. of 
soft soap, to each gallon; well mix the whole, and care- 
fully paint the entire surface of the walls with the pre- 
paration. 
TETRAPASMA. A synonym of Discaria (which 
see). 
TETRAPELTIS. A synonym of Otochilus (which 
see). 
TETRAPOGON (from tetra, four, and pogon, a 
beard; in reference to the bearded flowers). ORD. 
Graminee. A genus consisting of four species of hardy, 
tufted, often stoloniferous grasses, natives of North 
Africa, Abyssinia, and Western Asia. Spikelets two or 
three-flowered, clustered, secund, or nearly distichons ; 
spikes one, two, or three at the apices of the peduncles; 
glumes two, the lower one empty; stamens three. 
Leaves flat. T. villosus, the only species introduced, is 
of no horticultural value. 
TETRAPTERYS (from tetra, four, and pteron, a 
wing; the samaras are fonr-winged). ORD. Malpighiacew. 
A genus comprising about fifty-two species of usually | 
climbing, stove shrubs, natives of tropical America, 
mostly Brazilian. Flowers yellow or reddish; calyx five- 
parted, with eight glands, rarely ten or none; petals 
clawed; stamens ten, all perfect, the alternate ones 
longer; umbels or racemes often panicled, terminal, rarely 
sub-sessile. Leaves opposite, entire, often transparent, 
not glandular; stipules two, variable. The species are 
rather ornamental, but extremely difficult to bring into 
flower in this country, and it is donbtful whether those 
described below are still in cultivation. A compost of 
peat and sand forms the most desirable soil for them. 
Ripened cuttings will root in sand, under a hand glass, 
in heat. 
T, citrifolia (Citrus-leaved), A synonymof T. inwqualis, 
i w; icels hoary-pubescent, 
gitar eget ray aap ao 
May. slig 
1. elliptic or elliptic-oblong, bluntish or slightly acute, 
coriaceous, glabrous ; sti interpetiolar, deciduous. Guiana 
and Trinidad, 1827. 
, ineequalis (unequal). . yellow; petals articulated at or 
a the mate umbe. our-flowered, paniculate. May. 
1. ovate or elliptic, acute, coriaceous; stipules interpetiolar, 
u 
deciduous. Brazil and Jamaica, 1818. Syn. T. citrifolia. 
TETRAQUETROUS. Having four very sharp and 
almost winged corners or angles. 
TETRASTICHOUS. Having a four-cornered spike. 
TETRATHECA (from tetra, four, and theke, a 
cell; the anthers are sometimes four-celled). ORD. Tre- 
mandreæ. A genus embracing eighteen species of small, 
very pretty, glabrous or glandular-hairy, greenhouse, 
Australian shrubs. Flowers four or five-parted, rarely 
three-parted, possessing the peculiarity of only opening 
during bright sun and on -fine days, but closing on the 
approach of evening, or when rain is imminent ; stamens 
sub-biseriate. Leaves alternate, whorled, or scattered, 
Heath-like and entire or flat and toothed, or reduced to 
minute scales. A selection of the introduced species is 
here presented. They are rather difficult to cultivate. 
A compost of fibry peat, with plenty of silver sand in- 
termixed, is most suitable. Water must be very care- 
fully administered at all times, and only soft rain-water 
should be used. Propagation may be effected by cut- 
tings of the young wood, inserted in sand, under a bell 
glass, and kept well shaded. 
ir- . A. pink; sepals bearing a few glandular 
T, uiis ee nt «about Pag vod July. l almost all 
whorled in threes or fours, broadly ovate or — orbicular, 
obtuse or slightly acute, rarely exceeding jin. in the 
margins flat or scarcely recurved, cilia or nearly glabrous. 
Stems slender, erect, or diffuse, lft. to Sft. long. “ae 
a 
