small black flies
Diptera (Greek: in the meaning of "two", ptera means "wing") is a classification order of the Insecta class (insect) based on its characteristic wings using only a pair of flimsy wings functional for flight, while the other pair is merely a stabilizer auxiliary or as an airspeed detector (also known as a halterer) Although many insects can fly, but only diptera is considered a true fly because of this character.
Diptera has large facet eyes when compared to its body. Antenna can be short (Brachycera) as well as long (Nematocera).