174 ; PLANT LICE. 
The root lice are much more difficult to reach, but the rem- 
edies applied against the phylloxera will also be more or less 
effective against them. Some are the use of bisulphide of carbon, 
submersion in water, strong soap or tobacco washes applied to 
the soil above the crown, and soot and ashes. 
Like most other plant-lice this species has a very complicated 
life-history, some details of which are still unknown. 
“The common forms both on the root and above ground are 
wingless lice, not exceeding one-tenth of an inch in length, of a 
reddish-brown color, and abundantly covered, especially in the 
aerial form, with a flocculent waxy excretion. These are so- 
called agamic females, and reproduce themselves by giving birth, 
as observed by many entomologists, to living young indefinitely, 
perhaps for years, without the intervention of other forms. The 
newly born larve have none of the white excretion, which, how- 
ever, soon appears as a minute down when they begin to feed. 
These lice are also peculiar in lacking the honey-tubes common 
to most aphides, but exude the honeydew from the tip of the 
body. In October or November, or earlier in the South, among 
the wingless ones, numbers of winged individuals appear, which 
are also all females, and are the parents, as shown by the observa- 
tions, partly unpublished, of Messrs. Howard and Pergande, of 
a true sexed generation of minute, wingless, larviform lice, the 
females of which, as in the case of the grape root-louse, give 
birth to a single “winter egg.” This egg is attached within a 
crevice of the bark, and, probably, following the analogy of the 
phylloxera, hatches in the spring into a female aphid which 
originates a new aerial colony. 
“The winged females appear somewhat abundantly in autumn, 
and are one of the means of the dispersal of the insect. They 
are very minute, clear-winged, gnat-like objects, greenish-brown, 
almost black in color, with the body covered with more or less 
of the cottony excretion. 
“The aerial colonies are probably killed out every winter in 
the colder northern districts, but in the warmer latitudes the 
partly grown individuals, at least, survive protected in crevices 
or under bits of bark, and remain more or less active during 
winter and renew the colonies the following spring. This has 
been shown to be true in the District of Columbia, and also in 
