Horse flies live for 30 to 40 days although the total life span may take longer. The life expectancy of house flies depends on the living conditions and temperature. Horse flies go through four stages in their life cycle. The stages are egg, larva, pupa and adult. Visit http://www.orkin.com/flies/house-fly/life-expectancy-of-house-fly/ for more information.
The adult horse fly's life span is around 30 to 60 days, however, the total life cycle may take a lot longer. Most species of horse fly spent the entire winter in a larval state and pupate during spring and early summer. They then lay eggs