<Li> M. d. domestica Linnaeus, 1758 </Li> <P> The housefly (Musca domestica) is a fly of the suborder Cyclorrhapha . It is believed to have evolved in the Cenozoic era, possibly in the Middle East, and has spread all over the world as a commensal of humans . It is the most common fly species found in houses . Adults are grey to black with four dark longitudinal lines on the thorax, slightly hairy bodies and a single pair of membranous wings . They have red eyes, set further apart in the slightly larger female . </P> <P> The female housefly usually mates only once and stores the sperm for later use . She lays batches of about 100 eggs on decaying organic matter such as food waste, carrion or faeces . These soon hatch into legless white larvae, maggots . After 2 to 5 days of development, these metamorphose into reddish - brown pupae, about 8 mm (0.3 in) long . Adult flies normally live for 2 to 4 weeks, but can hibernate during the winter . The adults feed on a variety of liquid or semi-liquid substances, as well as solid materials which have been softened by their saliva . They can carry pathogens on their bodies and in their faeces, contaminate food and contribute to the transfer of food - borne illnesses . In numbers, they can be physically annoying and for these reasons they are considered pests . </P> <P> Houseflies have been used in the laboratory in research into ageing and sex determination . Flies appear in literature from Ancient Greek mythology and Aesop's The Impertinent Insect onwards . Authors sometimes choose the fly to speak of the brevity of life, as in William Blake's 1794 poem The Fly, which deals with mortality subject to uncontrollable circumstances . </P>

Where do flys lay eggs in a house