Veterinary Entomology: Insects of Phylum Arthropoda

Vocabulary flashcards reviewing classification, morphology, life cycles, and clinical veterinary significance of insect parasites including Diptera families, mosquitoes, midges, black flies, tabanids, muscids, and sheep keds.

Phylum Arthropoda

An invertebrate phylum whose name means 'joint foot'; arthropods comprise approximately $80\%$ of all animal species, with insects making up $76\%$ of those.

Simple Metamorphosis

A form of development characterized by three gradual life stages—egg, nymph, and adult—found in organisms such as lice, ticks, and mites.

Complex Metamorphosis

A developmental cycle comprising egg, larva, pupa, and adult stages, during which complete restructuring of the larva into an adult takes place during pupation (e.g., flies and fleas).

Insect Thorax

The middle body region of an insect that bears $6$ jointed legs and either $0$, $2$, or $4$ wings.

Myiasis

Also known as fly strike; a condition resulting from the parasitic infestation of living host tissues or wounds by fly larvae.

Culex species

A genus of small, delicate mosquitoes with long 14–15 segmented antennae that lay eggs in stagnant water and transmit West Nile virus to humans, horses, and birds (especially owls and corvid species).

Simulium species (Black Fly)

Small, stout-bodied flies with a humped back that lay eggs in fast-running water, possess serrated scissor-like mouthparts and a labellum, swarm in daylight during still air, and can kill livestock through salivary toxins.

Culicoides species (Biting Midges)

Very small flies ($<2\,\text{mm}$) known as 'No-See-Ums' that can penetrate screens, lay eggs in damp marshy areas, deliver disproportionately painful bites, and trigger allergic reactions in horses.

Family Tabanidae

A family of large, stout-bodied bloodsucking flies comprising horse flies (Tabanus sp.) and deer flies (Chrysops sp.) with complex metamorphosis, aquatic larvae, and mouthparts consisting of stylets and a spongy labellum.

Horse Fly (Tabanus species)

A large ($10\text{--}30\,\text{mm}$) tabanid fly with clear or uniformly cloudy wings that typically attacks and bites the legs and body of stationary animals.

Deer Fly (Chrysops species)

A smaller ($6\text{--}10\,\text{mm}$) tabanid fly characterized by dark bands or patches on clear wings that typically bites the head and shoulders of moving hosts.

Family Muscidae

A family of flies that includes house flies, face flies, stable flies, and horn flies; they lay eggs in manure, garbage, or decaying organic matter that hatch into maggots within $24\,\text{hours}$ or less.

Musca domestica (House Fly)

A non-biting muscid fly equipped with a spongy labellum that feeds on eye/nasal secretions and open wounds; it acts as a mechanical vector for bacteria and viruses rather than bloodborne agents.

Musca autumnalis (Face Fly)

A fly that feeds on host ocular and nasal discharges as well as bite wounds from other flies, oviposits exclusively in freshly passed cattle feces, and vectors Moraxella bovis.

Moraxella bovis

The bacterial agent of infectious bovine keratoconjunctivitis ('Pinkeye'), biologically transmitted between cattle hosts by the face fly (Musca autumnalis).

Stomoxys calcitrans (Stable Fly)

A bloodsucking fly resembling the house fly but possessing a pointed piercing proboscis; both sexes inflict painful bites, vector bloodborne diseases, and spend approximately $80\%$ of their life cycle off the host.

Haematobia species (Horn Fly)

A small biting fly with a bayonet-like mouthpiece that vectors bloodborne diseases, causes seasonal midline dermatitis, and spends the majority of its adult life directly on the host.

Seasonal Midline Dermatitis

A ventral skin irritation in livestock associated with the feeding activity and bites of Haematobia species (horn flies).

Melophagus ovinus (Sheep Ked)

An atypical, wingless, dorsoventrally flattened muscoid fly that lives its entire life cycle on sheep, possessing stout claws and pit-enclosed antennae, and causing anemia and wool damage.

Labellum

A fleshy, sponge-like expansion at the distal end of the proboscis in various flies (e.g., house flies and black flies) utilized for lapping or sponging liquid nourishment.