102 
SYSTEM OF NATURE. 
classes of apterous articulates ; and their relative position 
may be shown thus.— 
ANOPLURA. THYSANURA. CHILOPODA. 
CRUSTACEA. 
ACARIDEA. CHILOGNATHA. 
ARACHNIDA. 
I feel much more confidence in proceeding to the winged 
insects: these will be found to divide either into four or 
seven classes, thus.— 
Amorpha ; 
In which the penultimate state is provided neither with 
mouth nor organs of locomotion; consequently it neither 
eats nor moves, nor does it bear any resemblance to the 
perfect state. This group contains two classes of insects. 
Class I.— Lepidoptera ; in which the perfect insect 
has four fully developed wings, all of them covered 
with a kind of scales, which are symmetrically ar¬ 
ranged on each other, like the scales of a fish or the 
tiles of a house. 
Class II. — Diptera ; in which the perfect insect has 
two fully developed wings, and two merely rudimen¬ 
tary ones, which are distinguished by the name of 
halteres or poisers. 
