Alderfly
| Alderfly Temporal range:  | |
|---|---|
| Adult Sialis lutaria | |
| Scientific classification | |
| Domain: | Eukaryota | 
| Kingdom: | Animalia | 
| Phylum: | Arthropoda | 
| Class: | Insecta | 
| Order: | Megaloptera | 
| Family: | Sialidae Leach, 1815 | 
| Subfamilies | |
| See text | |
Alderflies are megalopteran insects of the family Sialidae. They are closely related to the dobsonflies and fishflies as well as to the prehistoric Euchauliodidae. All living alderflies – about 66 species all together – are part of the subfamily Sialinae, which contains nine extant genera.