CHAPTEE XX 



NEUROPTERA PLANIPENNIA SIALIDAE, ALDER-FLIES, SNAKE-FLIES 



PANORPIDAE, SCORPION -FLIES HEMEROBIIDAE, ANT-LIONS, 



LACEWINGS, ETC. 



Fam. VIII. Sialidae Alder-flies and Snake-flies. 



Four wings of moderate size, meeting in repose over the hack at 

 an angle ; the hinder of the two pairs slightly the smaller ; 

 the anal area S7nall or nearly absent, not plicate. Nervures 

 moderately numerous, transverse veinlets moderately numerous, 

 forming irregularly disposed cells. The metamorphosis is 

 great; there is a quiescent pupa. The larva has the mandihles 

 formed for hiting, armed with strong teeth. 



The Sialidae, though but a small family of only some six or 



eight genera, comprise 

 a considerable variety of 

 forms and two sub- 

 families Sialides and 

 Eaphidiides. The former 

 group has larvae with 

 aquatic habits possessed 

 of branchiae but no 

 spiracles. 



Sicdis lutaria is one 

 of the commoner British 

 Insects frequenting the 

 vegetation about the 

 banks of tranquil streams; 

 it is well known to 

 anglers, being used l)y 



them for a bait. According to Ronalds it is called the alder or 



Fig. 286. The alder-fly, Sialis lutaria. Britain. 

 A, With wings expanded ; B, in profile. 



