614 NEUROPTERA. 



FIFTH ORDER. TRICHOPTERA, (Gr. %, ihrix, hair, msgov, 

 pteron, a wing.) 



The genus Phryganea, (Plate XV. fig. 10,) which is the only 

 one of this order, is by some joined with the genera Hydropsyche 

 and Limnophilus, to form the family Phryganeidae, and referred 

 to the order Neuroptera. The insects of this order have four 

 membranous and reticulated wings ; the posterior pair are the 

 larger; the front pair are generally hairy, hence the name of 

 the order. The name of Caddis -flies has been given to these 

 insects which come from the various species of case-worms. 

 The larvae are inactive, residing in water, in a case formed of 

 bits of shells or sticks, or of sand or saw-dust. The pupa is 

 inactive. The Caddis -fly is often used as a fish bait. 



SIXTH ORDER, NEUROPTERA, (Gr. VBVQOV, neuron, nerve; megbv, 

 pteron, a wing.) 



This order of mandibulate insects exhibits a considerable 

 variety of characters. According to Westwood, it includes 

 twelve families. It is estimated to include not far from a thou- 

 sand species. These insects have usually four reticulated 

 nervures, (wings with horny divisions, thin, and lace-like.) The 

 wings are of unequal size ; instead of the hind-wings, there are 

 sometimes only pedicles or stems. The antennas are usually 

 short and bristly. The pupae are sometimes active and sometimes 

 torpid ; the larvae are six-footed and very active, mostly predaceous, 

 and either terrestrial or aquatic. 



The DRAGON-FLIES, Libellulidce, (genus Libettula,) include 

 nearly two hundred known species. To these we have already 

 referred. While on the wing, they deposit their eggs in water 

 and in it pass both their larva and pupa state, gliding through it, 

 or crawling about in the mud at the bottom. The hinder part of 

 the body has several leaf-like processes, which can be drawn 

 together or opened at pleasure. These close the opening of a 

 cavity having very muscular sides. When the Dragon-fly 

 wishes to move rapidly, it opens this cavity, which thus becomes 

 filled with water ; then by contracting the walls of the cavity, 

 it throws out the water forcibly, like a stream from a syringe ; 

 aided by the re-action produced by the jet against the surround- 

 ing fluid, the creature shoots forward, with its legs closely 

 packed along the sides. The pupa is no less active, fierce and 

 voracious than the larva, differing from it only in having upon 

 the thorax the rudiments of wings, which in the perfect insect 



