INSECTS 377 



the fly-fisher are copies of various may-flies, of which the two 

 drakes are examples, as are also many of the " duns " and 

 " spinners ". 



Stone-Flies are dull-coloured flattened insects with four mem- 

 branous wings which, when at rest, are disposed so as to overlap 

 the back and sides of the body. The antennae are long, and 

 there are usually two filaments of similar appearance attached 

 to the tip of the abdomen. The life-history resembles that of 

 the preceding two groups. Stone- Flies are widely distributed, 

 and include a large number of species. The best-known British 

 form is the Common Stone- Fly (Per la bicaudata], well known to 

 anglers as a good bait for trout. 



2. Flat-winged Neuroptera include Alder- Flies, Snake- Flies, 

 Scorpion-Flies, Ant-lions, Lace-wing Flies, and other forms, in 

 all of which there are four similar wings, not capable of being 

 folded, but turned back when at rest so as to lie either flat, or 

 sloping like the roof of a house. The adult possesses well- 

 developed mandibles, contrasting in this respect with the last 

 group of Neuroptera, in which the mouth-parts are much reduced. 

 There is a terrestrial or aquatic larva, which becomes a quiescent 

 pupa. 



The Alder- Fly (Sialis lutaria) (fig. 228), which figures on 

 the angler's list, is a brown insect with brownish wings, clumsy 

 body, and long antennae. The wings in repose cover the thorax 

 and abdomen in a roof-like manner. It is common on river- 

 banks in Britain. The cylindrical greyish eggs are deposited in 

 patches on the stems of grasses or rushes near the water, into 

 which the rapacious larvae that hatch out from them find their 

 way. Later on, they come out of the water and bury themselves 

 in the soil, where they become pupae. 



Snake- Flies, of which there are several British species (e.g. 

 Raphidia ophiopsis), are more slenderly built insects, sometimes 

 found in woods. They are distinguished by the presence of a 

 sort of neck, and there is an ovipositor in the female. The 

 rapacious larva is found in rotten wood, where it passes into a 

 pupa stage. 



Scorpion- Flies are much more abundant in this country than 

 Snake-Flies, and the Common Scorpion-Fly (Panorpa communis) 

 (fig. 228) may be taken as a type. The name is due to the fact 

 that the abdomen in the male ends in a pair of pincers, and its 



