1. Any one of more than 1800 species of insects belonging to the family Simuliidae, most of which feed on the blood of birds or mammals, including four genera with species that feed on humans.

2. A group of aphid species (Aphis fabae) that are pests of a wide variety of cultivated plant. The insects are about 2 mm long and mainly black, and are often attended by ants, which feed on their sugary excretions (honeydew).