16 INTRODUCTION. 



(Bibionida) ; the oakflies (Leptidce), 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. 



In all, we have over four thousand varieties of diptcra, 

 indigenous to this country, plates I 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 Dolichopodidcz, 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 " roofvvise " (plate 7, 

 fig- 72). 



The smaller boatmen are known as Corixa Striata (plate 7, 

 fig. 71), and the wing cases lie flat along the back when folded. 

 They are similar in habit to the former. It is curious to see 

 a swarm of them sporting on a. sunny afternoon. At first 

 glance it looks as though a good rise of blue duns was 

 going on, but closer observation will show that after a short 

 flight thev drop into the water again, and swim away amongst 

 the water weed. Woe betide them should the trout observe 

 their little game, which then has a tragic ending ! The Water 

 Measurers (plate 7, figs. 73 74) also belong to this class 



