{{Taxobox
| color = pink
| name = Sialidae
| image = Sialis spPCCA20050708-9036A.jpg
| image_width = 240px
| regnum = [[Animal]]ia
| phylum = [[Arthropod]]a
| classis = [[Insect]]a
| ordo = [[Megaloptera]]
| familia = '''Sialidae'''
| familia_authority = [[William Elford Leach|Leach]], 1815
}}

'''Alderflies''' are [[Neuroptera|neuropterous]] [[insect]]s of the [[Family (biology)|family]] '''Sialidae'''. They are closely related to the [[dobsonfly|dobsonflies]], and have long filamentous [[antenna (biology)|antennae]] and four large [[Insect wings|wings]], of which the [[anterior]] pair is slightly longer than the posterior. There is only one genus, ''[[Sialis]]'', in [[North America]] and [[Europe]], and a few other small genera elsewhere ([[Japan]], [[South America]]).

The females lay a vast number of eggs upon grass stems near water. The [[larva]]e are aquatic, active, armed with strong sharp mandibles, and breathe by means of seven pairs of abdominal [[Gill|branchial]] filaments. When full sized they leave the water and spend a quiescent [[pupa]]l stage on the land before [[metamorphosis]] into the sexually mature insect.

''Sialis lutaria'' is the commonest alderfly in the [[United Kingdom]]&nbsp;<ref>{{cite web |url=http://www.arkive.org/species/ARK/invertebrates_terrestrial_and_freshwater/Sialis_lutaria/more_info.html |title=Alderfly - ''Sialis lutaria'' |publisher=ARKive.org |accessmonthday=28 June |accessyear=2006}}</ref> and across much of Europe.

<gallery>
Image:Sialis lutaria larva (aka).jpg|''Sialis lutaria'' larva
Image:Megaloptera-sialidae-sp.gif|''Sialoide sp.''
</gallery>

==External links==
*[http://bugguide.net/node/view/143 BugGuide]
*[http://cedarcreek.umn.edu/insects/023001n.html Insects of Cedar Creek]

==References==
<references/>

{{commonscat|Sialidae}}

[[Category:Megaloptera]]

[[de:Schlammfliegen (Familie)]]
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