272 
NATURAL HISTORY. 
of a shining black colour; near these there is a black line 
on each side ; and the legs are very slender. 
'These animals are usually found upon the leaves of the 
orache, and other plants ; and the weaker the leaves and 
buds are, these insects swarm upon them in greater abun- 
dance. Some plants are covered over with them ; though 
they are not the cause of the plant’s weakness, but the sign : 
however, by wounding and sucking the leaf, they increase 
the disease. They generally assume their colour from the 
plant on which they reside. Those that feed upon pot- 
herbs and plum trees, are of an ash colour ; only they are 
greenish when they are young : those that belong to the 
aider and cherry-tree are black ; as also those upon beans, 
and some other plants: those on the leaves of apples and 
rose trees, are white. As they leap, like grasshoppers, some 
place them in the number of the nea kind. The most un- 
common colour is reddish : and lice of this sort may be 
found on the leaves of tansey ; and their juice, when rubbed 
in the hands, tinges them with no disagreeable red. All 
these live upon their respective plant, and are often engen- 
dered within the very substance of the leaf. 
All these bring forth their young alive; and the foetus, 
when it is ready to be biought forth, entirely fills the belly 
of the female ; its fore parts being excluded first, and then 
the hinder. The young one does not begin to move till 
the horns or feelers appear out of the body of the old one ; 
and by the motion of these it first shews signs of life, mov- 
ing them in every direction, and bending all their joints. 
When the horns and head are excluded, the two fore feet 
follow, which they move with equal agility ; after this follow 
the middle feet, and then the hinder : still, however, the 
young one continues sticking to its parent, supported only at 
one extremity, and hanging as it were in air, until its small 
and soft members become hardened and fitted for self-sup- 
port. The parent then gets rid of its burden by moving 
from the place where she was sitting, and forcing the young 
one to stand upon its legs, leaves it to shift for itself. 
As the animal has not far to go, its provision lying be- 
neath it, during the summer it continues to eat and creep 
about with great agility. But as it is viviparous, and must 
necessarily lurk somewhere in winter, where its body may be 
defended from the cold, it endeavours to secure a retreat 
near the trees or plants that serve to nourish it in the begin - 
ning of spring. They never hide themselves in the earth? 
like many other insects, because they have no part of their 
