Thaumatoniyia notata

These are small, yellowish flies with black markings which enter houses in the autumn, sometimes in enormous numbers. They can easily be confused with vinegar flies (p. 80), but they are a paler yellow; they do not visit foodstuffs and, in fact, are quite harmless indoors.

These small flies will nearly always be attracted to the upper storeys of a house and very often to houses covered with ivy or Virginia creeper, for this type of dense vegetation is their natural habitat.

The larvae feed on various grasses