United States Fish and Wildlife Service list of threatened and endangered arthropods species may be treated as endangered or threatened if it resembles in appearance a species which has been listed and enforcement personnel would have difficulty distinguishing between the listed and the unlisted species; if the effect of this difficulty is an additional threat to the listed species; and if such treatment of the unlisted species would improve protection for the listed species. United States Fish and Wildlife Service list of threatened and endangered arthropods List of threatened and endangered arthropods, including insects, arachnids, and crustaceans under the United States Endangered Species Act as of October 2013. Key to Listing Status
Parasitic flies of domestic animals transmitted organisms to develop, multiply and be exposed to further vertebrate hosts where they can complete their life cycle. Only the adult flies are involved in this biological transmission, in contrast to biological transmission by other arthropods such as lice or ticks in which all active stages of the life-cycle feed on blood. Typical genera are "Culex", "Aedes", and "Anopheles". The basic structure of dipteran flies is illustrated in the diagram. Veterinary parasitology also covers arthropods in the Class Acari, the ticks of domestic animals and mites of livestock which have distinctly different structure from arthropods in the Class Insecta.