black fly
| 1. | (Zool.) 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 | |
| 2. | A black plant louse, as the bean aphis (Aphis fabæ), which infests e. g. beans and sugar beets; - called also |
| Noun | 1. |  black fly - small blackish stout-bodied biting fly having aquatic larvae; sucks the blood of birds as well as humans and other mammalsSynonyms: buffalo gnat, blackfly |