CHAPTER XX 



NEUROPTEEA PLANIPENNIA SIALIDAE, ALDER-FLIES, SNAKE-FLIES 



PANOEPIDAE, SCOEPION- FLIES HEMEEOBIIDAE, ANT-LIONS, 



LACEWINGS, ETC. 



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



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

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

 the anal ay'ea small or nearly absent, not plicate. Nervures 

 moderately numerous, transverse veinlets moderately numerous, 

 forming irregularly disposed cells. The metamorphosis is 

 great; there is a qtdescent pupa. The larva has the mandibles 

 formed for biting, armed with strong teeth. 



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



I , 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. 



Sialis lutaria is one 

 of the commoner British 

 Insects frequenting the 

 vegetation about the 

 banks of tranquilstreams; 

 ^'°' A^ VP' ^^'^'"^^' '^/"f ' ^^""'™- «?"*^'°- it is well known to 



A, Witn wings expanded ; B, in profile. 



anglers, being used Ijy 

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



