Biting flies – deer flies and horse flies – belong in the family Tabanidae. They are members of the order Diptera. Dipteran is a true fly and as such many species are capable of spreading disease. Tabanidae is the family of beautifully colored flies with a nasty and painful bite. Painful in this case is a mild expression. The bite of a tabanidae is piercing as though someone has plunged a dull pair of rusty scissors into your arm and then forced them open. Once bitten by a horse fly or deer fly you become keenly aware of anything flying around in late spring through late fall. These are not small flies. In fact, horse flies can reach 25 mm in length. They are big, sturdy and agile flies that seem to hone in on you when you are least able to pay attention. They strike with the skill of a trained assassin, biting open your flesh and lapping up the blood before you can slap yourself so hard that it stings. Horse flies are excellent hunters and even the wariest of people fall prey to their chomping mouth parts. So how do biting flies find you? Let’s explore the prowess of these beautiful menaces.

Female Horse Flies Are Amazing Hunters
It is just the females that bite people. The males are plant sap suckers. The females, however, need blood from a warm-blooded creature to successfully reproduce. Horse flies and deer flies are such obnoxious pests that we have tried for decades and failed to eradicate them with pesticides. Yet, they are keen hunters. They use a variety of tools to find and target their prey and these are the things that allow them to find us with such ease. Here is a closer look at how they find us.

Compound Eyes
Horse flies have compound eyes. What that means is that they two eyes that consist of many individual lenses. They can see farther into the peripheral and a greater area than we can. However, they do not see clearly. What they see is a combination of bright and dark, shadow and shine. The targets of tabanidae are large mammals such as people, horses, cattle, deer, elk, and other animals with bulky bodies. Why is that? It is because, with compound eyes, they can see the shapes of larger animals easily. They track you by your movement. This is one of the reasons why they are so successful in hunting us. While sight is their main method of finding prey, it is not their only tool. Their antennae are adept at picking up chemtrails. More specifically, carbon dioxide which we exhale every time we breathe. Further, They can track us by our body heat which helps them distinguish us from darker surroundings. We cannot hide from them. They can find us by sight. They can find us by our carbon dioxide trail. They can find us because our body heat is within a specific range. This is why they are so successful.
It is how they hunt us that becomes their weakness. Pesticides do not work well on horse flies or deer flies. What does work are traps like the Fly Cage. The Fly Cage emulates the movement of large mammals. That movement draws the attention of deer flies and horse flies. They investigate their potential target but never return to breed, bite, or terrorize again.