10 
Other, sloping like the sides of a roof; and do not over-lap. The 
mouth arises from the hinder part of the under surface of the heau. 
This sub-order includes the cicadas or harvest-llies, the seventeen-year 
locusts, the tree-hoppers, leaf-hoppers, lantern-tlies, plant-lice, bark- 
lice, etc. 
It is divided by some entomologists into two sections, while others, 
as Westwood, divide it into three sections. These two plans are 
shown in the following brief, synoptical arrangement of the characters 
of these different sections. 
Subdivisions of Hoaioptera. 
it 
Section I.—Tarsi, or feet, three jointed; beak arising from the pos¬ 
terior portion of the under side of the head, but not apparently fiom 
the breast; wings present in the perfect insect in both sexes, and 
always four. This section contains all homopterous . insects except 
plant and bark-lice, 'therefore further notice of it is omitted. 
Section II.—Tarsi less than three jointed; beak arising apparently 
from the breast, between the front and middle legs; wings usually 
four when present, sometimes only two, often wanting in the females. 
Division 1. Tarsi two-jointed; wings, when present, four; antennae 
varying in length, but always longer than the nead, from thiee to ten- 
jointed; never changing in the perfect state into an apparently lifeless 
scale; a distinct beak present in both sexes. 
This division is named Dimer a by Westwood, from the two-jointed 
tarsi, and contains the various kinds of plant-lice. 
Division 2. Tarsi or feet one-jointed; wings present in the male 
onlv, and but two; the female changing, in the perfect state, into an 
apparently lifeless scale; the beak wanting in the peifect male. 
This division is named Monomera by Westwood, from the one-jointed 
tarsi, and contains only the bark-lice or scale-insects. 
The first of these ‘‘divisions,” Dimer a , which contains the plant-lice, 
is the only one we have to do with at present. It is divided into tnree 
families, Psyllidce, Aphididce and Aleurodidce , which may be distinguished 
from each other by the characters given in the following brief syn¬ 
opsis: 
Synopsis of the Families of Plant-lice. 
A. —The four wings transparent, or at least thin and membranous, and 
not covered with a mealy or farinose substance; pupae active and 
not scale like. 
^.—Possessing the power of leaping; the antennae thread-like com¬ 
posed of nine or ten (usually ten) joints, and tipped at the end with 
two minute but distinct bristles. 1. family Psyllid-e. 
BB.—Ss ot possessing the power of leaping; the antennae usually six 
or seven-jointed, though sometimes only three or five-jointed, and 
always without the two bristles at the tip. 2. Family— Aphididje. 
