shore fly

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun Any of various small flies of the family Ephydridae living in damp or marshy places, some of which are agricultural or horticultural pests.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A tiny fly found near seashores or at smaller inland waters, such as ponds, of one the the 1,500 species of the family Ephydridae.