Females are almost identical to the house fly, but males have an orange abdomen with black mark down the centre.
The female is approximately 1/4", and is generally larger than the male.
Breed in animal dung in fields.
Undergoes a complete metamorphosis with distinct egg, larva or maggot, pupal and adult stages.
The white eggs, about 1/32" in length, are laid singly but pile up in small masses. Each female fly can lay up to 500 eggs in several batches over a three to four day period.
The life cycle can be complete within 12–20 days depending on temperature, with as many as 12 OR several generations occurring in one summer.
The flies affect both horses and cattle, and are usually seen on the face often around the eyes.
At night they rest on vegetation or man-made structures. Most daylight hours are spent feeding on plant sugars, the surface of manure deposits, or on animals.
On host animals, they obtain protein from nasal mucus, saliva, and tears. The flies have microscopic “teeth” on their mouthparts, which are used to stimulate the flow of tears and aid this feeding process.
They are strong fliers and are capable of travelling several miles, but most stay within the vicinity of their breeding grounds.