to mites, and as larvae may be confused with them at infestations. The third tick family, the Nuttalliellidae, consists of one rare species. Ticks require separate accounts because they have distinctly different feeding mechanisms and relations to disease. Distinguishing acarines from insects (subphylum Hexapoda) is similarly important because the term 'insect' is often used in popular text and speech for various small crawling animals. The generalized anatomy of an acarine as shown in the diagram below can be compared with that of an insect as in typical parasitic flies of domestic animals. Outline classification Phylum: Arthropoda (insects, acarines, crustaceans, arachnids etc.) Subphylum: Chelicerata (acarines, scorpions, horseshoe crabs, solfugids, etc.) Class: Arachnida (mites, ticks, spiders, scorpions, etc.) Subclass: Acari (mites and ticks) [Superorders, orders and suborders omitted] Family: Psoroptidae (psoroptic mites) Family: Psorergatidae (itch mites) Family: Sarcoptidae (sarcoptic mites) Family: Cytoditidae (air-sac mites) Family: Laminosioptidae (fowl cyst mites) Family: Analgidae (feather mites) Family: Trombiculidae (trombiculid or chigger mites) Family: Demodicidae (follicle mites) Family: Dermanyssidae (blood-sucking mites of birds) also Family: Argasidae (soft ticks) also Family: Ixodidae (hard ticks) Lifecycles Mites have a lifecycle in which larvae hatch from the eggs, then feed and molt into nymphs. Several stages of nymphs may follow (another term for stages in this context is instar). The final molt produces an adult female or male. The early form of the female is described as pubescent (ready for mating) and may be equipped with protuberances that couple with matching sockets on the male during fertilization. Such coupled mites are a natural occurrence in skin-scrape samples of mites for diagnosis. Once mated, the female continues to develop and lay eggs; or in the typical case of Psoroptes for example, females produce one large egg at a time. In most parasitic mites, the entire lifecycle takes place on the host, with all stages present simultaneously (an exception is the trombiculid mites where the nymphs and adults are free-living). This type of lifecycle, with all active stages resembling each other in structure and feeding mechanism, is called incomplete metamorphosis (or hemimetabolism). A metamorphosis is a distinct change of body shape. When the larval stages of an invertebrate animal are completely different from the adult stage, as with caterpillars changing into butterflies, a complete metamorphosis occurs (holometabolism). Anatomy and morphology The parasitic mites are either just visible to the naked eye or one needs a microscope to see them clearly. The