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Parasite Image Database: Flies

The following images are provided as teaching aids to train and educate veterinarians. There are about 400 images on this site. Liberties were taken with parasite grouping to provide a veterinary medical emphasis.



Plebotomus sp.

Genus of sand flies that  vector Leishmania in the Old-World.


Lutzomyia sp.

Lutzomyia feeding on a spiny lizard (Sceloporus sp.). Lutzomyia is the new-world vector for LeishmaniaVesicular Stomatitis, and some Plasmodium species.



Culicoides sp.

Because of their small size, Culicoides, are often called no-see-ums. Even so, they have a painful bite, causing considerable annoyance to human and animal hosts, and enabling them to serve as a vector for the Blue Tongue Virus.

Culicoides hypersensitivity

Sweet itch, Queensland itch, Seasonal Recurrent Dermatitis, and Summer itch are all common names for condition caused by hypersensitivity of a horse to the saliva of Culicoides sp. Common areas to be affected include tailhead, mane, ears, and ventrum. Alopecia is secondary to pruritis.



Aedes sp.

Aedes mosquitoes are important vectors of Dirofilaria immitis as well as some viruses to humans and animals.


Anopheles sp.

Anopheles are important vectors of human malaria throughout the world.

culex; mosquito; integument; vector

Culex sp.

Magnified view of  the head of a male culicine mosquito. Culex is an important vector of many diseases including West Nile virus and avian malaria.


Muscid flies

horn fly; haemotobia; cattle

Haematobia irritans

Although it is known as the horn fly, H. irritans can be commonly found on the backs of cattle. To add to annoyance, they serve as a vector for Stephanofilaria stilesi. 


Haematobia irritans

Dorsal view of the horn fly. The majority of a horn fly's adult life is spent on its host, leaving only briefly to oviposit in fresh manure piles.



Musca autumnalis

Adults of Musca autumnalis, an important vector for pink eye (Moraxella bovis) and Thelasia sp., feeding on the eye secretions of a cow. Their preferential feeding habits is the basis for the common name, 'face fly'.


Musca domestica

The common house fly, M. domestica spreads filth and is a biological vector for Draschia megastoma and Habronema muscae. Note its sponging mouthparts.

Musca domestica

Four black stripes along the thorax of this fly aid in its identification.


fly; phormia; myiasis; integumentary; fly

Phormia regina

A member of the family Calliphoridae, Phormia regina is an important cause of secondary myiasis, or wound myiasis with a tendancy to invade not only necrotic tissue, but fresh tissue as well. Commonly known as the black blow fly, these flies are ubiquitous to the United States, though their times of peak activity vary by climate. 



Stomoxys calcitrans

The stable fly is distinguished from other parasitic flies by its emarginated eye.

Stomoxys calcitrans

Adult Stomoxys calcitrans prefer to feed on the distal limbs of cattle. However, most of their time as adults is spent elsewhere in the enviroment and they reproduce in piles of decaying organic matter.


Simulium and Tabanid Flies

Chrysops; fly; integumentary

Chrysops sp.

Female Chrysops ovipositing on a blade of grass above water. The female of the genus feeds on the blood of hosts while the male collects pollen. The females serve as an important mechanical vector for disease as well as a source of discomfort and loss of production for livestock.



Hybomitra; horse fly; fly; equine; integumentary

Hybomitra hinei 

A member of the family Tabanidae, Hybomitra hinei has been recorded as one of the fastest flying insects at a reported 145 km/h. It has been proposed that Tabanids use polarized light to orient themselves and thus are active only during daylight hours.



Simulium; buffalo fly; onchocerca; equine; vector

Simulium sp. female

Simulium, also known as the, "buffalo gnat," "black fly," or "humpback fly," are biting flies that swarm when they attack. There are reports of Simulium attacks resulting in the death of livestock and wildlife as a primary cause. Simulium is also known to vector various viruses such as Eastern Equine Encephalitis and Vesicular Stomatitis, along with various protozoa and nematodes such as Leucocytozoon and Onchocerca 

Simulium; fly; vector;

Simulium sp. larvae

Simulium lay their eggs on stones or plants just below the surface of the water in running streams. The eggs hatch in 4 to 12 days and the larvae attach themselves to rocks by means of a posterior organ that is armed with small hooks. Their anterior is equiped with a pair of brush-like organs with which they trap and ingest other insects.



Tabanus; vector; integumentary; fly

Tabanus americanum 

A member of the family Tabanidae, the genus Tabanus may be distinguished from other horse flies by its antennae. Its first two segments are distinctively short, while the terminal segment has a tooth like projection at its base.

Tabanus; fly; integument; bovine; equine; ovine; vector

Tabanus lineola

Known as the striped horse fly, Tabanus lineola is more commonly found in the eastern and southern United States, though it is not limited to this range. It's common for Tabanids to hold their wings horizontally when resting, as shown.



Tabanid; fly; integumentary; bovine

Tabanus melanocerus

A feeding female Tabanus melanocerus. Female Tabanids are well known blood-feeders but will also feed on honeydew and nectar as the males do. When biting a host, they cut the skin and lap up the blood that pools on the skin. This direct blood contact gives them the ability to act as a mechanical vector for many diseases. They also serve as biological vectors for Trypansosma theileri and Elaeophora schneideri


Cutaneous myiasis

Post docking cutaneous myiasis in a lamb.  Commonly known as "fly strike" or "fly blown" to producers. Possible species of facilitative myiasis-producing flies include; Musca domestica, Calliphora, Phaenicia, Lucilia, Phormia, Sarcophaga, and Chochliomyia macellaria.

Cochliomyia hominivorax and          C. macellaria

Cochliomyia hominovorax, primary screwworm, can be distinguished from C. macellaria, secondary screwworm, by its pigmented tracheal trunks.



Bot Flies

Cephenemyia sp.

Nasal bots of white-tailed deer, Cephenemyia can be found in the retropharyngeal space.


Cuterebra sp.

Cuterebra sp.

Severe infestation of Cuterebra in a vole. Adult Cuterebra deposit their eggs near the entrances of burrows belonging to potential hosts.

feline; Cuterebra; integumentary

Cuterebra sp.

Larval Cuterebra encysted in the neck of a cat. Infections of the cranial cavity of the cat has been reported as well as parasitic orchitis in the dog and cat, and dermal infections in humans.


Dermatobia hominis

Larval stage of Dermatobia hominis in the skin of a man. Human infections are usually associated with close living in proximity to domestic animals. Development in the host requires five to ten weeks. 

Dermatobia hominis

Extraction of Dermatobia hominis from the back of a bovine. The posterior end of the larva may be seen protruding through the hole it has cut through the dermis. Dermatobia hominis may infect cattle, dogs, cats, sheep, rabbits, and other animals including humans.

Bovine; Dermatobia; bot; integumentary

Dermatobia hominis

Larva of Dermatobia hominis. A member of the family Cuterebridae, D. hominis is found in tropical America, from Mexico to the Argentine. Adults lay eggs on the abdomens of biting flies which provide transportation as well as initial access into the dermis.

Gasterophilus sp.

Species of Gasterophilus can be differentiated according to patterns of spines on the bot larvae.


Gasterophilus sp.

Section of horse stomach infected with bots. Larvae tend to cluster together on the the non-glandular portion of the stomach, near the margo plicatus.

Gasterophilus nasalis

Migrating first stage larvae of Gasterophilus nasalis around the molar of a horse. First stage larvae will migrate for approximately 28 days before molting and moving to the stomach.

Gasterophilus sp.

Egg of a Gasterophilus sp. on a horse hair. Horse bot flies can oviposit between 150 and 100 eggs on a horse's body, typically during the early summer months.

Hypoderma sp. 

Adult Hypoderma, also known as the warble fly are non-feeding, as evident by their diminished mouth parts. Their adult life is short, usually less than a week, giving them only time to breed and oviposit.

hypoderma; bovine; integumentary

Hypoderma sp.

Nodules on the backs of cattle caused by encysted Hypoderma larvae, said to be in the, 'warble' stage. The larvae cut small holes or pores in the backs of cattle through which they respire. This stage lasts approximately 30 days before the larvae emerge through the pores and begin pupation on the ground.

Hypoderma sp.

The third-instar of Hypoderma can be found in subcutaneous nodules in the backs of cattle.

Hypoderma lineatum

Migrating first stage larvae of Hypoderma lineatum found on necropsy of a bovine. Adult female H. lineatum deposit their eggs below the hocks on the hair of cattle during the spring, the eggs hatch, larvae penetrate, and may be found around the esophagus during the winter.

Ovine; Oestrus; bot; respiratory

Oestrus ovis

Oestrus ovis larvae in the nasal turbinates of a sheep head cross section. Though the adults do not feed on animals, Oestrus is still considered parasitic as its larvae feed solely off the bodily fluids of their host. "False gid" is a condition wherein the larvae erode the bone of the skull and damage the brain, causing neurologic signs.



Melophagus ovinus

Melophagus ovinus is the sheep ked.  This wingless fly is most often confused for a louse and is sometime called the louse fly.