98 SUB-ORDER HOMOPTERA. 
Homoptera form a well marked group, so well defined that 
some entomologists consider it a distinct order; yet the families 
in it show very great variations in structure and modes of growth. 
The name Homoptera is derived from two Greek words: homos, 
same; and pteron, a wing. 
All Homoptera are plant-feeders, piercing the tissues of 
plants by means of lancets, and sucking the sap from the cells 
beneath. For this reason they are of more or less importance 
to the agriculturist, and, as a matter of fact, some of our most 
destructive insects belong to this order. They are most diffi- 
cult to combat, and stomach poisons, such as are applied to 
biting insects, are of no avail, hence contact poisons have to be 
resorted to. 
Prof. Comstock gives the following classification : 
A. Beak apparently arising from the sternum, 
or absent; tarsi one or two-jointed; 
antenne usually prominent and filiform, 
sometimes wanting. 
B. Tarsi one-jointed; adult male without 
any beak and with only two wings: 
female wingless, with body either 
scale-like or gall-like in form, or 
grub-like and clothed with wax. 
The waxy covering may be in the 
form of powder, of large tufts or 
plates, of a continuous layer, or of a 
thin scale beneath which the insect 
Lives ifs inde eee meee ee COCCIDAE. 
BB. Tarsi usually two-jointed; wings, when 
present, four in number. 
C. Wings opaque, whitish; wings and 
body covered with a_ whitish 
POWER... ds) sis Sis Arash raetepeaato aes ALEYRODIDAE. 
CC. Wings transparent. 
