LOU 
LOU 
till it bred in the fpring. But it appears that this 
infefl did not render him all that gratitude he had 
a 1 ight to expefl j for it fpeedily became the parent 
of a numerous progeny, and ravaged the beauti- 
ful phyfic-garden of that celebrated city. 
Louse, Leaf. The infe6l which naturalifts 
have defcribed under thp name of the Leaf- 
Loufe, is about the fize of a flea, and of a bright 
green or blueifh colour. The body, which is 
nearly oval, is largeft and moft convex on the 
hinder part; the breaft is very fmall ; and the head 
is blunt, and of a greenifli caft. The eyes are 
plainly diftinguifliable, being prominent on the 
fore-part of the head, and of a fhining black co- 
lour; near them there is a black line on each fidc; 
and tlie legs are very flender. 
Thefe infects are ufually found on the leaves of 
the orache, and other plants ; and the weaker the 
leaves and buds are, they fwarm on them in the 
greater abundance. Some plants are entirely over- 
fpread with them ; and though they are not the 
caufe of vegetable weaknefs, but the figns of it, 
yet by wounding and fucking the leaves they in- 
creafe the difeafe. Thev generally derive their 
colour from the plants on which they refide : thofe 
which feed on kitchen-herbs and plum-trees are 
of an afh- colour when full-grown, and greenifh 
while young; fuch as belong to the alder and 
cherry-tree are black ; and thofe which infell: the 
leaves of apple and rofe-trees, are white: but as 
the laft-mentioned leap after the manner of graf- 
hoppers, fome naturalifts have placed them in the 
number of the flea kind. The mofl: Angular co- 
lour aflTumed by thefe animals is red ; however, 
fome of this kind are found on the leaves of the 
tanfy, and their juice tinges the hands with a pretty 
lively red. All the various fpecies live on their 
refpe6live plants, and are often engendered within 
the fubftance of the leaf. They are all vivipa- 
rous; and the foetus, when ready to be brought 
forth, entirely fills the belly of the female. The 
young one does not begin to move till the horns 
or feelers appear out of the body of the fem.ale; 
and by the motion of thefe it firfl: indicates it's 
exifl:ence, moving them in every direftion, and 
bending all their joints. When the horns and 
head are excluded, the two fore-feet follow, which 
the infect moves with equal agility; after this, 
the middle feet appear, and then the hinder: fl:ill, 
hov/ever, the creature continues to adhere to it's 
parent, fupported only at one extremity, and fu- 
fpended as it were in the air, till it's fmall and 
foft members become hardened and adapted for 
felf-prefervation ; then the parent liberates herfelf 
from the burden by a progrefilve motion from the 
place where fiie was ftationed, which forces the 
young animal tofliand on it's ov/n legs, and thereby 
to fupport itfelf. 
As the food of this infe6t is generally obtained 
at no great diftance, it continues, during the fum- 
mer, to eat and creep about with great agility : 
but, being viviparous, it is neceffitated to lurk 
fomewhere in winter, where it's body may be de- 
fended from the cold; and accordingly, it endea- 
vours to fecure a retreat near fuch trees or plants 
as ferve to nourifli it in the beginning of fpring. 
It never buries itfelf in the ground, like many 
other infe<5ts, becaufe no part of it's body is fitted 
to remove the earth; nor can it creep into every 
chink, it's legs being too long : befides which, it's 
body is fo tender, that the leafl: rough particle 
of earth would injure it. It therefore takes up 
it's refidence in the deep fiflfures of the bark, and 
in tlie cavities of the fl:ronger fl:alks, from whence 
it fallies out on the branches and leaves when the 
genial warmth of the fun begins to return. Nei- 
ther the cold in the autumnal feafon, nor the lefi^er 
degree of heat in the fpring, ever hurts it: it fel- 
dom, therefore, feeks for a place of flicker before 
the fall of the leaf ; and it is generally alert enough 
to embrace the earlieft advantage of the returning 
fpring. 
Thefe infects fhed their flcins four times; after 
which the males acquire the like number of wings, 
but the females never get any. They have all 
long legs, which not only enable them to creep 
over the long hairs of trees and plants, but alfo 
to travel from one tree to another when fuch expe- 
ditions are neceflliry. Their trunks or fnouts lie 
under their breafl:s ; and thefe they thruft: into the 
pores of plants, in order to extraft their juices; 
for they do not gnaw them like caterpillars, but 
fo wound them by fucking, that the leaves be- 
come fpotted, and as it were over-run with fcabs. 
Some naturalifl;s have affirmed, that thefe in- 
fers are often feized and carried away by ants; 
but others, who feem to have paid much attention 
to the fubjeft, deny this aflfertion: ants, indeed^ 
Anew a partiality for thofe trees on which a great 
num.ber of thefe Lice are found, but then it is 
only to fuck the juice which flows abundantly 
from the leaves they have wounded. This more 
particularly happens during the heats of fummer, 
when other moifture is wanting; but it does not 
appear very probable that ants will attack thefe 
infefts ; for which indeed they are by no means a 
match. However, the Plant-Lice have three 
principal and conftant enemies, viz. the fire-fly, 
the beetle, and the ichneumon: the former lays 
it's eggs where thefe infedts are moft: numerous; 
and the latter, which is by far the moft formida- 
ble, feizes on one of the females, and drops it's 
egg in her body, which is foon after hatched into 
a worm that defl:roys the animal from whofe body 
it was produced. 
Louse, Wood, Common. This infect is 
about half an inch long, and a quarter of an inch 
broad: the colour is a livid black, efpecially when 
found in the vicinitv of dunghills, and on the 
ground; but thofe which refide under tiles, and 
in places more remote from moifliure, are of a ci- 
nereous colour. The Wood-Loufe has fourteen 
feet, feven on each fide; and two fliort feelers. 
The body is of an oval fliape; and the fides, near 
the feet, are dentated like a faw. When touched, 
it rolls itfelf up into a kind of ball. 
Thefe creatures are often found among rotten 
timber, and on decayed trees: in winter they lie 
hid in the crevices of walls. The males are eafily 
diftinguiinabie from the females, being lefs, and 
more flender. Their eggs are white and fliiining, 
like feed-pearls, and very numerous. However, 
though the young, when firfl: excluded, have every 
appearance of eggs, they are neverthelefs alive; 
and, without throvs^ing off any fhells, move about 
with great vivacity : fo that thefe animals may be 
properly fl;iied viviparous. They are of confi- 
derable fervice in medicine, being impregnated 
with a faline quality, Vv'hich is diuretic and ftimu- 
lating. Linnseus enumerates three fpecies of the 
Wood-Loufe. 
Louse, Sea. An appellation given to a An- 
gular fpecies of fifii, about a foot long, and co- 
vered with a fhell. It has the appearance of a 
round 
