TROGOSITA. 
mental, Australian, evergreen, ligneous plants, 
of the epacris tribe. The laurel-leaved species, 
7’. laurina, is a tree of about 25 feet in height, 
and carries white flowers from April till August ; 
it was introduced to British collections about 26 
years ago; and it loves a soil of sandy peat, and 
is propagated from cuttings. 
TROGOSITA. A genus of beetles of the bos- 
trichide family. The mandibles are shorter than 
the head, and crossed ; the ligula is almost square, 
and is not prolonged between the ‘palpi; and the 
maxille have but a single lobe. The Maurita- 
nian species, or the cadelle, 7rogosita Mauritant- 
cus, is very extensively known for the depre- 
dations of its larva upon various kinds of field 
and forest produce. It isa native of the north 
of Africa; but has been so profusely propagated 
thence, partly by natural immigration and partly 
in attachment to articles of importation, that it 
now occurs in America, and is very common 
throughout a great part of Europe, It is about 
four lines long, blackish above, and light brown 
beneath, and its elytra are striated. The beetle 
itself is carnivorous, and makes some amends for 
the mischief done by its larva by destroying the 
Tinea granella. How or where the female depo- 
sits her eggs is not yet known; but the larva has 
been bred by an experimentalist in a Spanish 
almond, and was found to live there during 15 
months, and the beetle which arose from it after- 
wards lived during 21 months,—so that the en- 
tire period of the creature is believed to be not 
less than 3 years. The larva, when full grown, 
is about 8 lines long and 1 line broad; its body 
is whitish, and comprises 12 segments, distinct 
enough, and rough with short scattered hairs; 
its head is hard, scaly, and black, and has two 
sharp, curved, horny jaws; each of the three 
thoracic segments has a pair of short scaly legs 
and a pair of obscure spots; and the anal seg- 
ment is terminated by two very horny hooks. 
The larva makes very great havoc among grain 
locked up in granaries, eating the outside of it, 
and passing so freely from one seed to another as 
to injure more than it consumes; and it also at- 
tacks dead trees, and even bread and nuts, and is 
very commonly found beneath the bark of trees; 
and when it has completed its period, it buries 
itself in the ground, and there undergoes trans- 
formation into a pupa. 
TROLLIUS. See Grose Frower. 
TROMOTRICHE. A genus of curious, South- 
African, evergreen undershrubs, of the swallow- 
wort tribe. Five genera, varying in height from 
6 to 25 inches, and carrying dark-coloured flowers, 
principally purplish, in June and succeeding 
months, have been introduced to British gardens; 
and they require the heat of the dry stove, and 
love a soil of sandy loam, and are propagated 
from cuttings. 
TRONA. The native sesquicarbonate of soda. 
t occurs on the banks of the alkaline lakes of Su- 
kenah in Africa, and is imported thencé to Britain. 
TROT. 49] 
TROPAIOLUM. See Inpran Cress. 
TROPHIS. See Ramoon Tree. 
TROT. The medium one of the three natural 
paces of the horse. See the articles Manzcr and 
Pacr. It comprises two varieties,—the slow and 
the swift; yet has been very generally described 
in terms which exclude the latter. In the slow 
trot—or what most persons regard as the only 
trot—the off fore leg and the near hind leg are 
simultaneously elevated and replaced, while the 
near fore leg and the off hind leg are on the 
ground, sustaining the whole weight and making 
ready for action, and vice versa. But in the swift 
trot, all the four feet, though moving in the 
same order as in the slow trot, or in diagonal 
pairs, are kept in such rapid action as to be all 
simultaneously in the air, each sustaining pair 
being off the ground before the alternate pair 
alight. “In the slow trot,” remarks Delabere 
Blaine, “ the near fore and off hind legs are pre- 
paring for elevation only, while the off fore leg 
and near hind are yet in action, and these raised 
legs are, in this instance, first set down before 
the near fore foot and off hind are actually re- 
moved from the ground. But in a fast trot these 
same feet are completely lifted from the ground, 
while the off fore and the near hind are yet in 
full progress. At this moment, it must. be clear 
that the horse is all in air; and it is this com- 
plete elevation from the earth which forms the 
essential difference between the slow and the 
extended trot. To pursue the description, the 
animal still acting on the impulse derived from 
the near fore and off hind, they become carried 
across the off fore and near hind at the moment 
these latter meet the ground. The off fore and 
near hind having met the ground, immediately 
prepare to rebound from it, and to give a fresh 
impetus to the motion before the near fore and 
off hind legs again come down; which then forms 
the second period when the horse is all in air, 
or, in other words, is again aérially elevated, and 
as totally detached from the ground as a bird 
when flying, or as the horse is understood to be 
when either leaping or galloping. If it should 
still not be readily comprehended how the horse 
should be without support at any time during 
the trot, let us draw a parallel between the pro- 
gression of a biped and that of the horse. In 
the walking of a man, one foot becoming elevated 
is carried forward, and set down,—during which 
the body is likewise carried forward, and the 
centre of gravity takes a new line through the 
moving mass; the contrary foot is now elevated 
also in its turn, and repeats all the phenomena 
of its fellow. In running, so essential a difference 
may be observed, that let running be conducted 
ever so slowly, and walking ever so fast, so that 
the speed shall be greatly in favour of walking, 
yet the paces will remain totally distinct. In 
the running of man, as well as in the extended 
trot of the horse, there is a period when all 
the supports are completely removed from the 
