Webster's Revised Unabridged Dictionary · 1913

black fly

black fly

1.
(Zoology) In the United States, a small, venomous, two-winged fly of the genus Simulium of several species, exceedingly abundant and troublesome in the northern forests; -- called also buffalo gnat. The larva are aquatic. It sucks the blood of birds as well as humans and other mammals.
2.
A black plant louse, as the bean aphis (Aphis faba), which infests for example beans and sugar beets; -- called also bean aphid.

Also: blackfly