Types of Flies in South Carolina: 7 Species Worth Knowing
September 23, 2026
South Carolina’s warm, wet climate makes it prime real estate for flies of every kind, from the biting tabanids that ruin a lakeside picnic to the tiny pollinators that quietly keep gardens thriving. Understanding the different types of flies in South Carolina helps you know which ones to avoid, which ones to appreciate, and which ones simply don’t deserve the bad reputation flies get as a group. This guide breaks down seven species you’re likely to encounter across the Palmetto State, from backyard patios to river bottoms.
Some of these flies bite hard enough to draw blood. Others never bite at all and instead spend their short lives pollinating flowers or breaking down decaying matter. Knowing the difference matters, especially during the warmer months when several species become far more active.
1. Deer Flies
Deer flies belong to the genus Chrysops, part of the Tabanidae family that also includes horse flies and yellow flies. Deer flies are generally smaller, ranging in size from 3/16 to 3/8 inch in length and are in the insect genus Chrysops. A widespread example in the region is Chrysops vittatus, a widespread tabanid in the Southeastern US.
Color is one of the easiest ways to tell deer flies apart from their relatives. Both deer flies and yellow flies tend to be yellow in color, but deer flies often have additional darker colors in the form of stripes or mottling especially on the thorax. Their wings carry a similar pattern, described by North Carolina State Extension as tinted smokey gray-brown or have dark patterns, and their thorax is greenish-yellow with dark stripes.
Unlike horse flies, which tend to target the legs of large animals, deer flies and yellow flies tend to feed from above, attacking the head and shoulders. That habit makes them especially unpleasant during hikes near ponds or marshes, since they prefer moist habitats like marshes, woodland ponds, and streams and rarely found near homes. South Carolina hosts a surprising amount of diversity within this group alone, as there are over a dozen species of deer flies in South Carolina.
Pro Tip: Deer flies are drawn to movement and dark colors. Wearing light-colored clothing and avoiding sudden swatting motions near wetlands can reduce how often they land on you.
The bites themselves are no joke. Bites can be very painful resulting in visible wounds, and tularemia can be transmitted to humans by the bite of a deer fly. Researchers with the South Carolina Pest Control Association note that these insects are most active during the warmer months, much like the grasshoppers and other meadow-dwelling insects covered in this guide to grasshoppers in South Carolina.
2. Horse Flies
Horse flies are the heavyweights of the Tabanidae family. Horse flies are about 3/8 to 1-1/8 inch in length and are in the insect genus Tabanus. North Carolina State Extension puts the range slightly differently, noting horse flies are moderate to large flies, 14 to 19 mm long, their wings are clear and their thorax grayish-brown, according to the NC State Extension horse fly and deer fly guide.
South Carolina’s most dramatic example is the Black Horse Fly, scientifically known as Tabanus atratus. The Edisto Island Open Land Trust describes it as a serious contender for the state’s largest biting insect, noting that measuring in at a bit over an inch in length, the Black Horse Fly is a contender for the state’s largest biting insect, and this fly is stoutly built, torpedo-shaped, and solid black from antennae to abdomen tip. Males and females look almost identical except for their eyes, since males have larger compound eyes that press against each other, leaving nothing but a seam between running down their forehead.
Important Note: Only female horse flies bite. Males feed exclusively on nectar and plant sap, while females need blood protein to develop their eggs.
Female horse flies are not picky eaters. Females are ectoparasites that bite and drink blood from large mammals, including deer, bear, bison, and elk, as well as more domestic animals like hogs, cows, and horses. Anyone keeping farm animals as pets in South Carolina will likely deal with these flies during the summer.
Reproduction ties horse flies closely to wetlands. Females lay their eggs in conical masses on the underside of a grass blade or leaf overhanging a pond, marsh, or other permanent wetland, and those eggs eventually hatch as the larvae plop down into the wetland below. The larval stage lasts far longer than most people expect: a white and gray banded maggot will feed on aquatic insects over the next two years, eventually growing to nearly two inches in length, before it crawls on land and pupates in the soil.
3. Yellow Flies
Yellow flies are frequently confused with their deer fly cousins, but they belong to a different genus entirely. Yellow flies are similar to deer flies but on average slightly larger and are in the insect genus Diachlorus. The regional species, Diachlorus ferrugatus, has earned a reputation as a fierce biter in Florida and across much of the Southeast.
Range-wise, yellow flies stretch well beyond South Carolina’s borders. According to Bug Out Pest Control, they’re found in the south-eastern parts of the United States from New Jersey to Texas and North Carolina, with physical traits close enough to deer flies that misidentification is common. Size-wise, yellow flies are medium-sized flies, typically measuring between 1/4 to 1/2 inch in length.
Like their tabanid relatives, only females bite. Like mosquitoes, it is the female fly that is responsible for inflicting a bite, as males are mainly pollen and nectar feeders. Females home in on hosts using the same cues mosquitoes rely on, since 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. Peak activity lines up with the hottest stretch of the year, as 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.
| Biting Fly | Genus | Typical Size | Color |
|---|---|---|---|
| Deer Fly | Chrysops | 3/16 – 3/8 in | Yellow with dark stripes/mottling |
| Horse Fly | Tabanus | 3/8 – 1 1/8 in | Black or dark gray |
| Yellow Fly | Diachlorus | 1/4 – 1/2 in | Yellow/golden |
4. House Flies
The common house fly is the most familiar fly on this list, and for good reason. House flies are usually between 4 mm – 7 mm in length, they are dark grey in color, and display a distinct pattern of four black lines on their thorax. Unlike the tabanids covered above, house flies don’t have biting mouthparts at all.
Their feeding habits are arguably worse than a bite. As Action Pest Services explains, house flies don’t bite, but they regurgitate saliva onto surfaces before consuming it, transferring bacteria directly onto everything they land on. That habit, paired with a breeding cycle where they breed in warm, decaying material and can go from egg to adult in under two weeks, explains why populations explode so quickly during South Carolina summers.
The health risk isn’t theoretical. House flies are carriers of bacteria, pathogens, and viruses that can spread illnesses such as diarrhea and even food poisoning. Households already managing outdoor pests like the species covered in this guide to ants in South Carolina often find house flies just as persistent indoors.
5. Fruit Flies
Fruit flies are tiny but hard to ignore once they show up in a kitchen. Scientifically named Drosophila melanogaster, these insects are among the common types of flies in South Carolina and the United States, and are also well-known all over the world. Physically, these flies have a short lifespan and measure around 3mm in length, with a body that has red eyes, and are commonly found near decaying fruits and vegetables where they feed on the yeast and bacteria that thrive in those environments.
Their reproductive speed is what makes them such a persistent nuisance. With a lifecycle of 10 to 14 days, these flies while they are still active can also be a nuisance, especially in kitchens, dustbins, or any other place where there are decaying fruits. The good news is that control rarely requires chemicals. If you want to get rid of these flies, you will need to do nothing other than remove fruits that have rotten or any rotten organic matter that could be in your home.
6. Mayflies
Mayflies look delicate compared to the biting flies above, and they behave nothing like them. Belonging to the order Ephemeroptera, mayflies vary in size, but most species have a 1 3/4 inch long body, with coloring that ranges from pale white to brown to black, and some also have bright streaks of yellow or some other color. Locally, mayflies in South Carolina are also called shadflies or lake flies.
One notable South Carolina species is the coffin fly, Ephemera guttulata, described as a type of fly that is native to South Carolina and the surrounding states. It’s a sizable mayfly, with a body length of about 15-20 millimeters and reddish brown or black wings, and it’s typically found near rivers, streams, and other water sources in moist areas.
Structurally, mayflies are easy to spot once you know what to look for. A mayfly typically has four wings and three long hair-like appendages that extend from the abdomen. Adult life is brief and purely reproductive, since adults live only a short period, enough time to mate and lay eggs, and they do not feed.
That short adult window makes mayflies a critical food source for the aquatic and semi-aquatic species covered in guides to frogs in South Carolina and salamanders in South Carolina, both of which rely heavily on mayfly larvae and emerging adults for food. Several bat species covered in this overview of bats in South Carolina also time their evening feeding around mayfly emergences near rivers and lakes.
7. Hoverflies
Hoverflies close out this list on a friendlier note. Members of the family Syrphidae, the most common bee mimics are the hoverflies, members of the Syrphidae family, which resemble small bees or wasps like yellow jackets. One species documented in South Carolina is the Hornet Mimic Hover Fly, Volucella zonaria, a large syrphid that ranges up to roughly an inch across.
The resemblance to stinging insects is a defense strategy, not a coincidence. This phenomenon, called Batesian Mimicry after Henry Walter Bates, describes the phenomenon of harmless species mimicking unrelated harmful species as a form of protection from predators. According to NC State Extension entomologists, many hoverflies, which don’t sting, mimic bee species that do, making predators think twice before grabbing them.
Key Insight: Hoverflies are genuinely beneficial garden visitors. Their larvae hunt aphids while adults pollinate flowers, making them one of the few flies worth encouraging rather than swatting.
Their larvae do real work in gardens and crop fields. Most hoverflies have free-living predatory larvae, and hoverfly adults lay eggs on plants near aphid colonies, where the maggots move within the aphid colony grabbing aphids with their mouths and eating them. That pest-control service extends into agriculture, since hoverflies can be valuable for biological control of aphids in crops like lettuce and grains on which aphids are common pests. Gardeners who appreciate pollinators covered in this guide to bees in South Carolina or the species featured in this overview of butterflies in South Carolina will likely recognize hoverflies as regular visitors to the same flowers.
South Carolina’s fly population runs the full spectrum, from the tabanids that leave a lasting welt to the hoverflies quietly working through an aphid colony. Learning to tell a deer fly from a yellow fly, or a house fly from the far tinier fruit fly, makes a real difference for anyone spending time outdoors or dealing with an indoor infestation.
Many of these species also play understated roles in the wider ecosystem covered in this list of endangered animals in South Carolina and the food webs those species depend on, and the beetles profiled in this guide to beetles in South Carolina share many of the same wetland and garden habitats. Whether the goal is avoiding a painful bite or supporting garden pollinators, knowing which fly is which is the first step.