Yellow Flies


Actual Size: ⅜”

Characteristics: Predominantly yellow; bright green eyes, clear wings with black veins. The forelegs are predominantly black, the other pairs yellow.

Legs: 6

Antennae: Yes

Wings: Yes

Habitat: Congregate in shaded, humid areas on the edges of forests, rivers and creeks, avoiding large, open, sunny areas.


  • Sometimes mistaken for deer or horse flies.
  • Like mosquitoes, female yellow flies require a blood meal before they can reproduce.
  • Bites are painful, often causing large and itchy swellings that can last for several days.

Yellow flies, belonging to the Tabanidae family,  are sometimes mistaken for deer or horse flies and are just as unwelcome due to their painful bite. Found in the south-eastern parts of the United States from New Jersey to Texas and North Carolina, their physical appearance is similar to deer flies and many people get confused when trying to identify them. Like mosquitoes, it is the female fly that is responsible for inflicting a bite, as males are mainly pollen and nectar feeders. Yellow flies are most likely encountered in the heat of summer and early fall weather and are known for their painful bites and aggressive behavior, making them a nuisance for outdoor activities and livestock alike. 

Take a look at the most common flies found in North Carolina to help identify the specific fly species.


Yellow Fly Identification


What Do Yellow Flies Look Like?

Yellow flies are medium-sized flies, typically measuring between 1/4 to 1/2 inch in length. They have robust bodies with a yellow or golden coloration, which gives them their name. Their wings are clear and often have distinct dark markings. One of the most recognizable features of yellow flies is their large, prominent eyes, which are often brightly colored and iridescent.

Signs of a Yellow Fly Infestation

Signs of a yellow fly infestation may include the presence of these flies in outdoor areas, particularly near water sources such as ponds, rivers, and marshes. Additionally, individuals and animals may exhibit symptoms of yellow fly bites, such as redness, swelling, and itching around bite sites.


Habitat, Diet, Lifecycle & Bites


Where Do Yellow Flies Live?

Yellow flies inhabit wooded areas, near water bodies, and humid environments, particularly active during warmer months. They seek blood meals from large mammals like humans, livestock, and pets. Adults are strong fliers, often found near larval habitats, but may travel for blood. They gather in shaded, humid areas on forest edges, rivers, and creeks, avoiding sunny spots. Larvae thrive in deeply shaded areas, submerged beneath water surfaces. Preferring warm, humid weather, they’re most active during daytime, especially before twilight. While domestic animals are readily targeted, their preference for shade reduces pestering in open pastures.

Diet of a Yellow Fly

Yellow flies feed on the blood of mammals, including humans, as well as birds and other animals. Female yellow flies require blood meals to obtain the necessary nutrients for egg development and reproduction. Male yellow flies primarily feed on nectar and plant juices and do not bite.

Life Cycle of a Yellow Fly

The life cycle of a yellow fly consists of four stages: egg, larva, pupa, and adult. Female yellow flies lay their eggs near water or in moist soil, where the larvae hatch and develop. The larval stage typically lasts several weeks, during which the larvae feed on organic matter and decaying vegetation. Once mature, the larvae pupate and emerge as adult flies, ready to seek out hosts for blood meals and reproduction.

Yellow Fly Bites

Yellow fly bites can be painful and irritating, often resulting in redness, swelling, and itching at the bite site. In some cases, individuals may experience allergic reactions or secondary infections if bites are scratched excessively or not properly treated.


Are Yellow Flies Dangerous?

While yellow flies are not known to transmit diseases to humans, their bites can be painful and may lead to discomfort, itching, and potential allergic reactions in sensitive individuals. Additionally, repeated exposure to yellow fly bites can cause stress and irritation to livestock and other animals, leading to reduced productivity and potential health issues.

How to Get Rid of Yellow Flies?

To effectively get rid of yellow flies, begin by minimizing their breeding habitats. Eliminate standing water sources and organic debris, as these are prime breeding grounds. Use yellow fly traps or sticky traps specifically designed to attract and capture adult flies. Wear light-colored clothing and avoid wearing floral or brightly colored attire that may attract them. Additionally, consider using outdoor fans or citronella candles to create airflow and deter yellow flies. By implementing these measures, you can effectively manage and reduce yellow fly populations in your surroundings.

If you are dealing with a persistent black fly problem on your property, contact your local fly exterminators.

Yellow Fly Prevention Tips

  • Eliminate Breeding Sites: Reduce yellow fly populations by eliminating standing water and areas of stagnant moisture where flies may breed, such as clogged gutters, water troughs, and bird baths.
  • Trim Vegetation: Keep lawns, shrubs, and vegetation well-trimmed to reduce harborage areas for yellow flies and make outdoor spaces less inviting to these pests.
  • Use Animal Repellents: Apply animal repellents or fly sprays to livestock and pets to deter yellow flies and minimize bites.



What Are Yellow Flies Attracted To?

Yellow flies are attracted to carbon dioxide, body heat, and movement, making them particularly drawn to humans and animals as potential hosts for blood meals.

What Is the Difference Between Yellow Flies and Horse Flies?

Yellow flies and horse flies are both members of the Tabanidae family and share similar characteristics, including robust bodies and biting mouthparts. However, yellow flies are typically smaller in size and have a distinct yellow or golden coloration, while horse flies are larger and may have darker coloration.

What Attracts Horse Flies to Humans?

Horse flies are attracted to humans by factors such as body heat, carbon dioxide emissions, and movement. They are known to target humans and animals as hosts for blood meals, which they require for egg development and reproduction.

What Are the Yellow Flies with Green Heads?

The yellow flies with green heads are likely referring to a specific species of tabanid fly known as Chrysops spp. These flies are commonly found in wooded areas and are known for their distinctive green-colored heads and robust bodies.