BITING FLY is a term used to describe a group of insects that feed on the blood of other animals. The three crossword solutions for this term are GNAT (4 letters), MIDGE (5 letters), and TSETSE (6 letters). Gnats are small, two-winged flies that are often found in large swarms. MIDGE is another name for a GNAT, but it can also refer to any small fly. TSETSE flies are larger than gnats and midges, and they are known for transmitting sleeping sickness in humans and animals.