Medically-important
Guides
Buthidae
fat-tailed scorpions, bark scorpions, arrowbreasted scorpions
Buthidae is the largest family of scorpions, containing approximately 100 genera and 1300 species as of 2025. Members are typically mid-sized to small, with weak, slender pedipalps and characteristically thickened tails. The family has a cosmopolitan distribution throughout tropical and subtropical environments worldwide. Buthidae includes nearly all medically significant scorpion species, with venoms containing potent neurotoxins that affect ion channels.
Centruroides
bark scorpion, bark scorpions
Centruroides is a highly speciose genus of buthid scorpions comprising at least 100 species distributed throughout the southern United States, Mexico, Central America, the Antilles, and northern South America. Commonly known as bark scorpions, members of this genus are notable for their strong fluorescence under ultraviolet light—except immediately after moulting—and several species possess venom potent enough to cause human fatalities. The genus includes species adapted to diverse habitats ranging from tropical rainforests to arid regions, with some showing marked intra-domiciliary tendencies in urban environments.
Limulus polyphemus
Atlantic horseshoe crab, American horseshoe crab
Limulus polyphemus is a marine and brackish chelicerate arthropod commonly known as the Atlantic or American horseshoe crab. Despite its common name, it is more closely related to spiders, ticks, and scorpions than to true crabs. The species has remained morphologically unchanged for approximately 200 million years, earning it the designation of a 'living fossil.' It is ecologically and medically significant, with populations distributed along the Atlantic coast of North America and in the Gulf of Mexico.
Megalopyge
flannel moths, puss moths
Megalopyge is a genus of moths in the family Megalopygidae, commonly known as flannel moths or puss moths. The genus contains approximately 50 described species distributed primarily in the Americas. Larvae are densely covered in hair-like setae that conceal venomous spines, making them medically significant due to severe stinging reactions in humans. Adults are relatively small, stout-bodied moths with reduced mouthparts.
Tabanus lineola
striped horse fly
Tabanus lineola, commonly known as the striped horse fly, is a biting horse fly native to eastern and southern North America. Females are aggressive blood-feeders of humans and livestock, recognized by a pale median stripe on the abdomen, while males lack this feature, do not bite, and have bare eyes. The species has a univoltine life cycle with larvae developing in saturated sandy soils near water bodies.