Rusalki

The lovely river nymph of southern Russian legend endowed with human beauty and the gentle characteristics of the Mermaids of northern European nations. Shy and benevolent, she lived on the small alluvial islands that stud the rivers or in the detached coppices of their banks. Her pastime and occupation was to aid in secret the poor fishermen in their laborious and precarious calling.

The rusalki (also spelled "rusalky" or "rusalka") were believed to have originated with young women who met an untimely death either by suicide, drowning, or murder by strangling or were not buried in holy ground. At times the rusalki would turn on people and kill them, especially young men who would go bathing in the streams without wearing a cross around their necks.

Little is known of these beautiful creatures. Thomas Keightley, a knowledgeable source in the lore of fairies, says little of rusalki in his book The Fairy Mythology (1850) and gives only this brief notice:

"They are of a beautiful form, with long green hair; they swim and balance themselves on the branches of trees, bathe in the lakes and rivers, play on the surface of the water, and wring their locks on the green meads at the water's edge. It is chiefly at Whitsuntide that they appear; and the people then, singing and dancing, weave garlands for them, which they cast into the stream."

Sources:

Arrowsmith, Nancy, and George Moorse. A Field Guide to the Little People. New York: Wallaby, 1977.

Cherryh, C. J. Rusalka. New York: Ballantine Books, 1989.