INTRODUCTION. 11 



The Ephemeridee 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 wings when at rest are closed together nearly 

 vertically over and in line with the body of the insect. 



The Perlidcs vary in size considerably and have four 

 membraneous wings smoky in colour, the hind pair much larger 

 than the upper pair ; the neuration is complex and looks brownish 

 against the light. Most insects have small heads, a thorax, and an 

 abdomen. In contrast to this the Perlidce have well-developed 

 heads, a pro-thorax, and also a metathorax ; in consequence, the 

 legs are widely separated. When at rest the wings are folded flat 

 or else furled along the body. 



Trichoptera, or Phryganidcs, 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, caterpiUar-like, usually 

 inhabiting cases of their own construction. 



Chrysopides, the Lacewing flies, fragile insects, with four 

 beautiful gauzy wings, which fold over their back roofwise, are 

 remarkable for their brilliant gold or ruby coloured eyes, which 

 possess a remarkable brilliance ; and, lastly, the 



SialidcB, of which there is only one British species that has two 

 pairs of dusky wings, the hind pair slightly smaller, and both heavily 

 veined, which also close roofwise when at rest. 



The Ephemeridee (Plates 3 and 4), of which there are over 

 forty species, form one of the most important classes to anglers. 

 From early Spring to late Autumn they are seen in swarms about 

 the water with a curious up and down flight, winging their way 

 before the wind or quietly floating down the stream with wings 



