236 
HEMIPTERA. 
the hinder extremity with two little tubes, knobs, or pores, 
from which exude almost constantly minute drops of a fluid 
as sweet as honey; their heads are small, their beaks are 
very long and tubular, their eyes are globular, but they have 
not eyelets, their antennae are long, and usually taper to- 
wards the extremity, and their legs are also long and very 
slender, and there are only two joints to their feet. Their 
upper are nearly twice as large as the lower wings, are 
much longer than the body, are gradually widened towards 
the extremity, and nearly triangular; they are almost ver- 
tical when at rest, and cover the body above like a very 
sharp-ridged roof. 
The winged plant-lice provide for a succession of their 
race by stocking the plants with eggs in the autumn, as 
before stated. These are hatched in due time in the spring, 
and the young lice immediately begin to pump up sap from 
the tender leaves and shoots, increase rapidly in size, and 
in a short time come to maturity. In this state, it is found 
that the brood, without a single exception, consists wholly 
of females, which are wingless, but are in a condition imme- 
diately to continue their kind. Their young, however, are 
not hatched from eggs, but are produced alive, and each 
female may be the mother of fifteen or twenty young lice 
in the course of a single day. The plant-lice of this second 
generation arc also wingless females, which grow up and 
have their young in due time; and thus brood after brood 
is produced, even to the seventh generation or more, with- 
out the appearance or intervention, throughout the whole 
season, of a single male. This extraordinary kind of prop- 
agation ends in the autumn with the birth of a brood of 
males and females, which in due time acquire wings and 
pair ; eggs are then laid by these females, and with the 
death of these winged individuals, which soon follows, the 
race becomes extinct for the season. 
Plant-lice seem to love society, and often herd together 
in dense masses, each one remaining fixed to the plant by 
