ARTIIROPODA. 
295 
flies, or Devil’s Darning-needles (. Libellula ), well known 
by the enormous head and thorax, large, prominent eyes 
(each furnished with twenty-eight thousand polished 
lenses), and Scorpion - like abdomen; the delicate and 
short-lived May-flies (Ephemera) \ Caddis-flies ( Phryga - 
nea ), whose larvae live in a tubular case made of minute 
stones, shells, or bits of wood; the Horned Corydalis 
(' Corydalus ), of which the male has formidable mandibles 
twice as long as the head; and the White Ants (Termes) 
of the tropics. 
2. Orthoptera have four wings: the front pair some¬ 
what thickened, narrow, and overlapping along the back; 
the hind pair broad, net-veined, and folding up like a fan 
Fig. 264.—Metamorphosis of a Cricket ( Gryllvs ). 
upon the abdomen. The hind legs are usually large, and 
fitted for leaping, all the species being terrestrial, although 
some fly as well as leap. The eyes are small, the mouth 
remarkably developed for cutting and grinding. The lar- 
