Ofv. Ak. Forh. xi. 1854, p. 302, pl. v., since confirmed by others, see Giard, C.R. Ac. Sci. cix. 1889, pp. 79 and 708.
Natural History of Aquatic Insects, 1895, p. 198.
Ent. Zeit. Stettin, vi. 1845, p. 384, pl. i.
Ann. Soc. ent. France (6) iii. 1883, p. 23, pl. i.
Ent. Nachr. xviii. 1892, p. 13.