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Family Sialidae - Alderflies

Unknown insect - Sialis Nearctic Alderfly with eggs - Sialis ID challenge - Sialis Alderfly - Sialis Alderfly - Sialis Alder fly ? - Sialis Alderfly Larva - Sialis Alderfly Larva - Sialis
Kingdom Animalia (Animals)
Phylum Arthropoda (Arthropods)
Subphylum Hexapoda (Hexapods)
Class Insecta (Insects)
Order Megaloptera (Alderflies, Dobsonflies, and Fishflies)
Family Sialidae (Alderflies)
Other Common Names
Orl-fly (1)
Explanation of Names
see Sialis
a single genus with 24 spp. in our area(2); 75 described spp. in 7 genera worldwide (of which 53 spp. in Sialis)(3)
Small to medium-sized, typically 10-25 mm
Medium-sized insects with soft bodies and large, delicate wings. Similar to fishflies, Corydalidae, usually smaller. These characters differentiate:
Wings folded roof-like over back at rest
Lack ocelli (simple eyes)
Fourth tarsal segment widened, has two lobes
Wing venation:
most speciose in Holarctic; among minor genera, one is Neotropical + Madagascar (12 spp.), two are restricted to Australia (4 spp.), one Oriental (3 spp.), one East Asian (2 spp.), and one South African (1 sp.)(3)
Adult are most often encountered in association with riparian vegetation adjacent to open water; larvae prefer ponds and lakes but can also be found in large rivers or pools in smaller, faster, streams where there is abundant silt. Some species appear to be restricted to warm streams, and some species are tolerant of polluted water.(3)
Adults generally appear to be largely non-feeding and may depend primarily on reserves sequestered in the larval stages.(3)
Life Cycle
Larvae are aquatic:
Adults found, briefly, on vegetation near the aquatic habitats; they are rather short-lived, rarely persisting over two weeks. Females deposit eggs in one or more masses, generally on the stems or leaves of plants overhanging water.(3)
Adults are relatively weak fliers and are rarely found far from water; most active on warm, sunny days, especially in the morning(3)
See Also
Plecoptera (Stoneflies) -- superficially similar but unrelated
Works Cited
1.American insects
Vernon L. Kellogg. 1905. H. Holt and Company.
2.Species catalog of the Neuroptera, Megaloptera, and Raphidioptera of America North of Mexico
Penny N.D., Adams P.A., Stange L.A. 1997. Proc. Calif. Acad. Sci. 50: 39-114.
3.Neuropterida Species of the World catalogue (by J.D. Oswald)