Frit Flies (Chloropidae) or Grass Flies are very common in meadows and grassy areas, though they are present in other habitats.  There are about 280 species in North America with about 3,000 described species in over 200 genera distributed worldwide. These are usually very small flies (1-4 mm), yellow or black and appearing shiny due to the virtual absence of any hairs. The majority of the larvae feed mainly on grasses and can be major pests of cereal crops. However, parasitic and predatory species are known and some are kleptoparasites.