Published online by Cambridge University Press: 15 May 2009
All observers agree that Musca domestica comprises over 90 percent. of the flies found in houses; my own observations show 97 percent. M. domestica is most easily distinguished by the venation of its wings, the fourth vein being bent up at an angle, and by the four longitudinal black stripes on the thorax. It is thus easily distinguished from Homolomyia canicularis, another somewhat smaller fly which frequents houses and forms the bulk of the remaining 3—10 per cent.