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CHAPTER XVII. 
Order Trichoptera (Tri-chop'te-ra). 
The Caddice-flies or Caddice-worms. 
The members of this order have four wings; these are 
membranous , furnished with numerous longitudinal veins but 
with only few cross veins , and are more or less densely clothed 
with hairs . The mouth-parts are rudimentary . The meta¬ 
morphosis is complete . 
The Caddice-flies are moth-like insects which are com¬ 
mon in the vicinity of streams, ponds, and lakes; and they 
are also frequently attracted to lights at night. 
The body-wall of these insects is soft, being membran¬ 
ous or at the most parchment-like, and is thickly clothed 
with hairs. There are usually four ample wings. These 
are membranous ; but the fore pair are more leathery than 
the hind pair. When not in use they are folded against 
the sides of the abdomen, in an almost vertical position, 
and give the insect a narrow and elongated appearance 
(Fig. 225). The wings are more or less densely clothed 
with hairs; and in some cases the 
hairs are scale-like in form. The hind 
wings are usually broader than the 
fore wings, and are often longitudi- 
fig. 22 5 .-Caddice-fly. nally folded in repose. All have nu¬ 
merous longitudinal veins, but the cross veins are few. 
The name of the order is from two Greek words: thrix , 
a hair; and pteroji, a wing. 
The order includes only a single family, the Pliryganeidce . 
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