Flies

Sandflies

Phlebotomus sp.
Genus of sand flies that vector Leishmania in Europe, Africa, and Asia.

Lutzomyia sp.
Lutzomyia feeding on a spiny lizard (Sceloporus sp.). Lutzomyia is a vector for Leishmania spp. and vesicular stomatitis virus in the Americas.

Biting Midges

Culicoides sp.
Because of their small size, Culicoides or biting midges are often called no-see-ums. Even so, they have a painful bite, causing considerable annoyance to human and animal hosts. Horses often become allergic to the bites. Culicoides sp. also serve as a vector of bluetongue virus

Culicoides hypersensitivity
Sweet itch, Queensland itch, seasonal recurrent dermatitis, and summer itch are all common names for a condition in horses caused by hypersensitivity to the saliva of Culicoides sp. Common affected areas include the tail head, mane, ears, and ventrum. Alopecia occurs secondary to pruritus.

Mosquitoes

Aedes sp.
Aedes mosquitoes are important vectors of heartworm (Dirofilaria immitis) and several viruses important in veterinary medicine and public health.

Anopheles sp.
Anopheles are important vectors of human malaria throughout the world.

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.

Horn Flies, Face Flies, and Stable Flies

Haematobia irritans
Although it is known as the horn fly, H. irritans can be commonly found on the backs of cattle. In addition 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)

Musca domestica
The common house fly, Musca domestica, is a mechanical vector of many infections and is a biological vector for Draschia megastom a and Habronema muscae.

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

Phormia regina
A member of the family Calliphoridae, Phormia regina is an important cause of secondary or wound myiasis with a tendency to invade both necrotic and fresh tissue. Commonly known as the black blow fly, these flies are ubiquitous in the United States; times of peak activity vary by climate.

Stomoxys calcitrans
The stable fly is recognizable by its emarginated eye and distinct proboscis which projects forward. Although usually associated with cattle and horses, this fly may occasionally be found feeding on dogs and is also known as the dog fly or kennel fly.

Stomoxys calcitrans
Adult Stomoxys calcitrans prefers to feed on the distal limbs of cattle. However, most of their time as adults is spent elsewhere in the environment. Stable flies reproduce in piles of decaying organic matter.

Horse Flies, Deer Flies, and Black Flies

Chrysops sp.
Female Chrysops ovipositing on a blade of grass above water. Female deer flies feed on the blood of hosts and serve as important mechanical vectors for pathogens as well as a source of discomfort and loss of production for livestock.​

Hybomitra hinei
A member of the family Tabanidae, Hybomitra hinei has been recorded as one of the fastest flying insects with a reported speed of 145 km/h. Tabanids are thought to use polarized light to orient and horse flies are active only during daylight hours.

Tabanus americanum
Tabanus americanum may be distinguished from other horse flies by its antennae. The first two segments are distinctively short, while the terminal segment has a tooth like projection at the base.

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. Tabanids hold their wings horizontally when resting, as shown.

Tabanus melanocerus
A feeding female Tabanus melanocerus. Female Tabanids are well known as blood-feeders but will, like males, also feed on plant fluids. When feeding on blood, they cut the host skin and then lap the pooled blood. Horse flies serve as mechanical vectors for many pathogens and as biological vectors for Trypanosoma theileri and Elaeophora schneideri.

Simulium sp. female
Simulium spp., also known as black flies, buffalo gnats, or humpback flies, are biting flies that swarm when they attack. There are reports of Simulium sp. attacks resulting in the death of livestock and wildlife. Simulium is also known to vector viruses (e.g. Eastern Equine Encephalitis, Vesicular Stomatitis), protozoa (e.g. Leucocytozoon sp.), and nematodes (e.g. Onchocerca spp.).

Simulium sp. larvae
Simulium spp. females deposit 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 equipped with a pair of brush-like organs with which they trap and ingest other insects.

Myiasis

Cutaneous myiasis
Post-docking cutaneous myiasis in a lamb. This condition is commonly known as "fly strike" or "fly blown" to producers. Genera of facultative myiasis flies include Musca, Calliphora, Phaenicia, Lucilia, Phormia, and Sarcophaga.

Cochliomyia hominivorax
The pigmented tracheal trunks of larval Cochliomyia hominovorax , primary screwworm, allow it to be distinguished from larvae of Cochliomyia macellaria , secondary screwworm.

Bot Flies

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

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

Cuterebra sp.
Larval Cuterebra sp. encysted in the neck of a cat. Infections of the cranial cavity of the cat have been reported as well as parasitic orchitis in both dogs and cats, and dermal cysts in humans.

Dermatobia hominis
Larval stage of Dermatobia hominis in the skin of a person. Infections with the human botfly are most commonly reported from Central and South America. 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.

Dermatobia hominis ​
Larva of Dermatobia hominis. A member of the family Cuterebridae, Dermatobia 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. A single female horse bot fly can oviposit between 150 and 1000 eggs on a horse, typically during the early summer months.

Hypoderma sp.
Like all bot flies, adult Hypoderma are non-feeding, as evident by their diminished mouth parts. Adult bot flies live only one to two weeks, allowing enough time to mate and oviposit.

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 in the soil.

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 lineatumlarvae. Adult female Hypoderma lineatum deposit eggs below the hocks on the hair of cattle during the spring. The eggs hatch, larvae penetrate, and begin to migrate through the host. Larvae of H. lineatum may be found around the esophagus during the winter.

Oestrus ovis
Oestrus ovis larvae in the nasal turbinates of a sheep head cross section. "False gid" is a condition wherein the larvae erode the bone of the skull and damage the brain, causing neurologic signs.

​Keds (Wingless Flies)

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