The egg is about 1 mm long and creamy white. It is curved on one side and straight and grooved on the other. About 1.25 mm long, the young larva is translucent and difficult to see. The puparium is soft and yellowish at first, but it soon becomes hard and reddish-brown. It is 4.25 to 6 mm long and wider at the head end.
Stable flies are worldwide pests of livestock and man.
Reported in the United States as early as 1912, these flies are now found throughout North America and are often numerous throughout North Carolina. They can, when numerous, weaken livestock by their blood sucking activities. They also interrupt cattle's normal feeding and resting activities, which in turn reduces weight and milk production. Besides being vicious biters, stable flies may transmit animal diseases such as hog cholera. However, manure piles are not favorable breeding sites.