INTRODUCTION. 17 



of these organs. The mouth parts are formed for sucking, and 

 sometimes take the form of a proboscis, which can be retracted at will. 

 The usual larval form is a small grub or maggot without feet. 



Those which most interest us are the Tipulidce or Crane-flies 

 (plate 1, figs. 1-5) ; they are all useful to anglers, but in their larval 

 stages, a scourge to farmers, doing great damage to the roots of their 

 crops. The Winter Gnats {Limnobince) also belong to this family. 



Examples of the Mosquitoes (Culicidcs), of which we have about 

 ten varieties, and the Gnats (Chironomidce), of which two hundred 

 species are indigenous to this country, are shown on plate 1, figs. 6-10. 



Included in the Diptera are the Syriphidce or Hoverers, of brilliant 

 yellow and black, which possess such marvellous powers of flight ; 

 the Woodflies (Sarcophagidce) ; the Blow-flies (Bibionidce) ; the 

 Oakflies (Leptidcs), dear to the angler more from early association 

 than actual use ; the Empidce or Snipe Flies, which prey on other 

 insects ; their head and mandibles resemble that of a woodcock, 

 and of necessity to catch their prey, they are exceedingly quick 

 of flight. (Plate 2.) 



In all, we have over four thousand varieties of Diptera, indigenous 

 to this country, plates 1 and 2 showing a few typical varieties. 



There are also two now mentioned for the first time, which 

 are favourites, and yet new to the angling world at large ; one is 

 the Silver Tail (Theriva nobilata), plate 2, fig. 21, and the other, 

 fig. 27, of the Metallic-flies or Dolichopida', which are exceedingly 

 common at the waterside, and quite worth imitating. 



V. Hemiptera. — Many of these are purely aquatic, including 

 the Water Boatmen, which are, no doubt, familiar to most anglers. 

 These are fierce insects, which attack other insects, tadpoles, and 

 small fry. They have a powerful beak which renders their attacks 

 very formidable, and swim with a curious jerky motion, coming to 

 the surface occasionally to take in air. They are good fliers, and on 

 the wing look rather like a bee. The largest is Notonecta glanca. 

 The elytra fold up over the body compactly " roof wise " (plate 7, 

 fig. 72). In the water it is readily distinguished by the fact that 



B 



