Sialis is a genus of alderfly belonging to the order Megaloptera family Sialidae.
Description These alderflies are small and mainly brown with a relatively heavy body and forewings reaching a length of 10 to 20 millimeters. Females are usually larger than males. They have wings with large cells forming a network. The upper edge of the front wings consists of almost square cells. The species belonging to the genus Sialis have less than fifteen square cells, while the other Megaloptera have more cells. The adults are diurnal and fly from May to June on the riparian vegetation.
Females lay on the leaves of the shore plants up to 2000 eggs in groups of about 200. The resulting hatching larvae fall directly into the water. They live in the water at first, and later buried in the mud, up to 18 meters of depth. These larvae feed on larvae of insects, worms and small molluscs. They usually need two years to develop, overwintering as larvae. Pupation takes place on the shore under the soil.
Distribution Species of this genus are present in most of Europe.
List of species This is a complete list of Sialis species as of 2026.
Sialis abchasica Vshivkova, 1985 Sialis aequalis Banks, 1920 Sialis americana (Rambur, 1842) Sialis annae Vshivkova, 1979 Sialis arvalis Ross, 1937 Sialis atra Navás, (1928) Sialis bifida Hayashi & Suda, 1997 Sialis bilineata Say, 1823 Sialis bilobata Whiting, 1991 Sialis californica Banks, 1920 Sialis chilensis McLachlan, (1871) Sialis concava Banks, 1897 Sialis contigua Flint, 1964 Sialis cornuta Ross, 1937 Sialis didyma Navás, 1916 Sialis dorochovae Vshivkova, 1985 Sialis dorsata Say, 1823 Sialis dreisbachi Flint, 1964 Sialis elegans Liu & D. Yang, 2006 Sialis flavicollis Enderlein, 1910 Sialis formosana Esben-Petersen, 1913 Sialis frequens Okamoto, 1905 Sialis fuliginosa F. Pictet, 1836 Sialis fumosa Navás, 1915 Sialis glabella Ross, 1937 Sialis gonzalezi Vshivkova, 1985 †Sialis groehni Wichard, 1997 Sialis hamata Ross, 1937 Sialis hasta Ross, 1937 Sialis henanensis Liu & D. Yang, 2006 Sialis imbecilla Say, 1823 Sialis immarginata Say, 1823 Sialis infumata Newman, 1838 Sialis iola Ross, 1937 Sialis itasca Ross, 1937 Sialis japonica van der Weele, 1909 Sialis jianfengensis D. Yang et al., 2002 Sialis joppa Ross, 1937 Sialis klingstedti Vshivkova, 1985 Sialis kouwenkaii Tu et al., 2023 Sialis kunmingensis Liu & D. Yang, 2006 Sialis levanidovae Vshivkova, 1980 Sialis longidens Klingstedt, (1932) Sialis lutaria (Linnaeus, 1758) Sialis martynovae Vshivkova, 1980 Sialis melania Nakahara, 1915 Sialis melania ssp. kyushuensis Hayashi & Suda, 1995 Sialis melania ssp. melania Nakahara, 1915 Sialis melania ssp. tohokuensis Hayashi & Suda, 1995 Sialis melania ssp. toyamaensis Hayashi & Suda, 1995 Sialis mohri Ross, 1937 Sialis morio Klingstedt, (1933) Sialis morrisoni K. Davis, 1903 Sialis muratensis Nel, 1988 Sialis nevadensis K. Davis, 1903 Sialis nigripes E. Pictet, 1865 Sialis nina Townsend, 1939 Sialis occidens Ross, 1937 Sialis rotunda Banks, 1920 Sialis sibirica McLachlan, 1872 Sialis sinensis Banks, (1940) Sialis sordida Klingstedt, (1933) Sialis spangleri Flint, 1964 Sialis strausi Illies, 1967 Sialis vagans Ross, 1937 Sialis vanderweelei Aspöck & Aspöck, 1983 Sialis velata Ross, 1937 Sialis versicoloris Liu & D. Yang, 2006 Sialis yamatoensis Hayashi & Suda, 1995 Sialis zhiltzovae Vshivkova, 1985
References
Ekkehard Wachmann, Christoph Saure: Netzflügler, Schlamm- und Kamelhalsfliegen, Naturbuch-Verlag, Augsburg 1997 Wilfried Wichard: Schlammfliegen aus Baltischem Bernstein (Megaloptera, Sialidae). In Mitt. Geol.-Paläont. Inst. Univ. Hamburg. 80: S. 197–211, 2 Abb., 9. Taf., Hamburg 1997.
External links Biolib Fauna Europaea