Yellow fly on a person's arm - Keep yellow flies out of your home with Kona Coast Pest Control in Kailua Kona

Yellow Fly

Actual Size: ⅜”

Characteristics: Long yellow bodies with black forelegs. The eyes are blue-green.

Legs: 6

Antennae: Yes

Wings: Yes

Habitat: Gather in shaded and humid locations along the borders of forests, rivers, and creeks, steering clear of expansive, sunny spaces.


  • Known for their painful bites.
  • Often mistaken for deer or horse flies.
  • Bites are painful, often causing large and itchy swellings that can last for several days.
  • Similar to mosquitoes, female yellow flies require a blood meal before they are able to reproduce.
Featured Image

Yellow Flies in Kailua Kona

Yellow flies, sometimes mistaken for deer or horse flies, are equally unwelcome owing to their painful bites. These insects are found in the southeastern regions of the United States, spanning from New Jersey to Texas and Florida. Resembling deer flies in appearance, they often cause confusion during identification. Similar to mosquitoes, it is the female yellow fly that delivers the bites, as males primarily nourish themselves on pollen and nectar. The likelihood of encountering yellow flies is highest during the warmth of summer and early fall, making awareness of their presence crucial for those in affected areas.

Yellow Fly Habitat

Adult yellow flies are skilled fliers and are commonly found in proximity to their larval habitat, yet they may cover substantial distances to seek a blood meal. These flies tend to gather in shaded, humid environments along the edges of forests, rivers, and creeks, avoiding extensive, sunny areas. The larvae, whether aquatic or semi-aquatic, are often situated in deeply shaded areas within root mats of trees, always beneath the water surface. Yellow flies thrive in warm and humid weather conditions, displaying heightened activity during the daytime just before twilight. While domestic animals, including dogs, are readily targeted, the fly’s preference for shade reduces its impact on cattle and horses in open pastures.

Yellow Fly Behaviors, Threats, or Dangers

The University of Florida states that the bite from the female yellow fly is categorized as one of the most severe bites. Like mosquitoes, female yellow flies must obtain a blood meal to facilitate reproduction. Adult females actively bite humans throughout the day, with heightened activity in late afternoons on overcast days. Yellow fly bites are known for their pain, often causing sizable and itchy swellings that can endure for days. If symptoms of infection, such as fever, nausea, headaches, or swollen lymph nodes, manifest after a yellow fly bite, seeking medical attention is highly recommended. For more information on yellow flies, contact your local fly exterminator.