Lesser house fly
General The genus Fannia comprises almost 300 different species of fly, including the lesser house fly , the latrine fly and a whole host of other man [...] are considered a serious pest because: The males form swarms above the ground at head height inside barns and hen houses, making them a particularly annoying [...] of up to 100 on animal feces, moist organic matter or carrion. The brown larvae that emerge after a few days are typically flattened, with a fringe of spiny