INTRODUCTION. 9 



I. The Neiiroptera, or nerve-winged flies, have two pairs 

 of wings, both pairs membraneous with extensive neuration ; 

 certain Ephemera, whicli have only one pair, make an 

 exception to this rule ; the imago has a biting mouth. 



By neuration is meant the system of nerves which con- 

 stitute the framework that supports the membrane of the 

 wings. 



The imago is the final stage of development of any insect. 



Selecting again only those families of the Neuropiera of 

 interest to anglers, we have the following : — 



May Flies, Duns, etc. 



Perlidce ... ... ... Stone Flies or Needle Flies. 



Trichoptera or Phryganidcs Caddis Flies. 



Chrysopidce ... ... Lace Wings. 



SialidcB ... ... ... Alder Flies. 



The Ephemera are delicate insects with atrophied mouths 

 and small short antennae, or feelers ; usually having four 

 membraneous wings, having much minute cross veining, the 

 hinder pair much smaller than the other pair and sometimes 

 entirely absent ; the body terminating in three or two elongate 

 slender tails. 



The PerlidcB are insects of moderate or large size, with 

 four membraneous wings complexly reticulate, the hind pair 

 much the larger and of more simple neuration ; the legs are 

 widely separated. 



Trichoptera, or Phryganaridce, as they are variously called, 

 form a connecting link between flies and moths, and have 

 always rather puzzled entomologists ; their wings are more or 

 less clothed with hair, the nervures divide at very acute angles 

 with very few transverse nervules, hind wings larger than the 

 front ones ; antennae and legs often long, though not so in all 

 species ; mandibles, or lower jaws, absent or rudimentary ; 

 larvae, caterpillar-like, usually inhabiting cases of their own 

 construction. 



