284 COMPARATIVE ZOOLOGY. 
Insects (the six-footed Articulates) comprise four-fifths 
of the whole Animal Kingdom, or about 200,000 species. 
They are grouped into seven orders: 
Lower series: body usually flattened; prothorax large seth Neuropters, 
squarish ; mouth-parts usually adapted for biting; met- i Orthopters, 
amorphosis incomplete; pupa often inactive; larva flat- | Hemipters, 
tened, often resembling the adult. | Coleopters. 
Higher series: body usually cylindrical; prothorax small; 
mouth-parts more generally formed for sucking; meta- 
morphosis complete; pupa inactive; larva usually cylin- 
Dipters, 
} Lepidopters, 
yal ters. 
drical, very unlike the adult. | VMAs 03 2: 
1. Neuropters have a comparatively long, slender body, 
and four large, transparent wings, nearly equal in size, 
membranous and lace-like. Such are the brilliant Drag- 
on-flies, or Devil’s Darning-needles (Zzbellula), well known 
by the enormous head and thorax, large, prominent eyes 
Lo 
Fie. 255.—Dragon-fly (Libellula), 
(each furnished with 12,000 polished lenses), and Scor- 
pion-like abdomen; the delicate and short-lived May-tlies 
(Ephemera); Caddis-flies (Phryganea), whose larve live 
in a tubular case made of minute stones, shells, or bits 
