midge n.

name given to gnat-like insects the females of which bite animals and draw blood through a piercing and sucking proboscis, 1580s, from Spanish mosquito "little gnat," diminutive of mosca "fly," from Latin musca "fly," from PIE root *mu- "gnat, fly" (compare Sanskrit maksa-, Greek myia, Old English mycg, Modern English midge, Old Church Slavonic mucha), perhaps imitative of the sound of humming insects. Related: Mosquital. Mosquito-hawk as a name for a kind of dragon-fly which preys on mosquitoes is from 1737. Mosquito-net "gauze or other fabric used as a screen against mosquitoes" is from 1745.

as a type of tiny biting insect, 1839, American English, from midge, perhaps with diminutive suffix -et.

Dr. Webster is in error in saying the word "midge" is "not in use" at the present day. In the neighboring Green mountain districts, one or more most annoying species of Simulium that there abound, are daily designated in common conversation as the midges, or, as the name is often corrupted, the midgets. From Dr. Harris' treatise it appears that the same name is in popular use for the same insects in Maine. The term is limited in this country, we believe, exclusively to those minute insects, smaller than the musketoe, which suck the blood of other animals. ["Transactions of the New-York State Agricultural Society," vol. vi, Albany, 1847]

Transferred sense of "very small person" is attested by 1854. It is also noted mid-19c. as a pet form of Margaret.