SCLEROCHLOA. 
a few delightfully fragrant. The roots and seeds 
of most of its species are more or less aromatic ; 
and those of some—such as the roots of ginger 
and the seeds of cardamon—occupy a most dis- 
tinguished place among the aromatics of the ma- 
teria medica. Nearly 150 species, belonging to 
11 or 12 genera, have been introduced to the gar- 
dens of Britain ; and nearly all require hothouse 
culture. 
SCLERANTHUS. See Kwawet 
SCLEROCHLOA. A genus of hardy, annual 
grasses of the fescue tribe. The procumbent 
species, S. procumbens, is a weed of the sea-coasts 
of Britain, and has a height of 6 or 7 inches, and 
blooms in July and August; and the rigid spe- 
cies, S. rigida, is a weed of sandy grounds in 
Britain, and has about the same height as the 
preceding, and blooms in June and July. These 
two species are popularly called hard grass ; and 
are assigned by some botanists to the genus poa. 
Four species—but none of them economically 
interesting—have been introduced from other 
countries. 
SCOLOPENDRIUM. See Hart's Tonavz. 
SCOLYMUS. See Gonpun TuIstiz. 
SCOLYTUS. A genus of the xylophagous 
family of beetles. It is distinguished, along with 
the genera tomicus, hylurgus, and hylesinus, for 
its devastations upon timber. See the article 
BostricHipm. It has nine joints in the antenne 
below the club, strong and obtusely triangular 
mandibles, short and four-jointed maxillary pal- 
pi, cylindrical body with the apex of the abdo- 
men obliquely truncated, and four-jointed tarsi. 
The destroying scolytus, S. destructor, has ex- 
cited vast attention on account of its enormous 
devastations upon avenues and groves and plan- 
tations of elm. The perfect insect is black and 
shining, and about 2% lines long; its head is 
clothed with short yellowish hairs ; its thorax is 
large and finely punctured ; its elytra vary in 
- colour from almost black to almost chestnut, and 
have each seven punctured strig ; its abdomen 
is hairy ; and its legs and antenne are dull red. 
The larva is a small, white, fleshy grub, desti- 
tute of legs, and pretty similar in appearance to 
the larva of the nut weevil ; its head is smooth 
and horny, and has noantenne ; its jaws are ob- 
tuse and strong ; its body is curved into a semi- 
circle ; and the segments are transversely chan- 
nelled. This insect, though for 12 or 15 years 
past threatening many of the elm plantations of 
England and of the environs of the principal 
cities of northern continental Europe with ex- 
termination, was not known to entomologists as 
an elm destroyer till about the year 1624, Ex- 
tensive injuries inflicted by it, in St. James’ 
Park, Hyde Park, Greenwich Park, Camberwell 
Grove, and other parks and promenades around 
London, were ascribed to human malice or mis-: 
_ conduct, and occasioned angry excitement and 
legal investigation, but eventually suggested in- 
quiry by competent naturalists under the autho- 
157 
SCOLYTUS. 
rity of government, and led to the full discovery 
of the true cause, An indiscriminate felling and 
uprooting of many thousands of diseased trees 
was resorted to for extirpating the insect, but 
was found to produce little or no effect ; and the 
signal failure of so very costly and deplorable a 
resource urged investigators onward to the 
eventual discovery of a true though still costly 
remedy. Hrosions are made by the female bee- 
tle and by the larve in the bark, the inner bark, 
and the alburnum ; and whenever these become 
very numerous, they so greatly interrupt the as- 
cent of the sap and the descent and assimilation 
of the cambium as to cause the death of the tree. 
“The female insect commences its injury about 
July by boring through the bark, until she has 
reached the part between the soft wood and in- 
ner bark, when she forms in the latter a vertical 
channel usually upwards of two inches long, on 
each side of which she deposits her eggs as she 
advances to the number of from 20 to 50. About 
September the larve are hatched, when they 
commence feeding upon the matter of the inner 
bark, at the edge of the channel, and in a very 
slight degree on that of the soft wood opposite, 
advancing as they feed, in a course of about 
right angles from the primary channel and on 
each side of it. When the larva has finished its 
course of feeding, it stops in its progress, turns 
to a pupa, and then to a beetle; after which it 
gnaws a straight hole through the bark and 
comes out. The beetles come out about the lat- 
ter end of May, in the year following that in 
which the eggs are deposited ; the sexes after- 
wards pair, and the female, bearing eggs, bores 
through the bark, and so on from generation to 
generation, and from year to year. The infested 
trees may be easily recognised, as the bark will 
be found perforated by small holes, as if made 
by a shot or broad-awl, in several parts, whilst 
small particles like saw-dust will be found on the 
rough surface of the bark, and at the foot of the 
tree. The scolyti never attack dead trees; they 
seldom destroy the trees they attack, the first | 
year that they commence their ravages; and 
they prefer a tree that they have already begun 
to devour, to a young and vigorous tree. It is 
stated that at least 80,000 have been known to 
attack a single tree. From observations made, 
it appears that the females never deposit their 
eggs in trees perfectly healthy, but that both 
they and the males pierce young and healthy 
trees for the purpose of eating the inner bark 
which constitutes their food, and that the numer- 
ous holes they thus cause, partly from the loss 
of sap which exudes from them and the absorp- 
tion of rain which lodges in them, will bring the 
trees in which they occur into that incipient 
state of ill health, in which the females select 
them for laying their eggs, and that thus healthy 
trees are effectually destroyed by the combined 
operations of the scolyti of both sexes, though 
not solely in consequence of the depositure of 
i _ 
