Indoor
Guides
Philodromus marxi
Metallic Crab Spider
Philodromus marxi is a running crab spider in the family Philodromidae, commonly known as the metallic crab spider. The species exhibits strong sexual dimorphism: males have a smooth, metallic sheen while females are bristly and colored white and grey. It is found throughout the United States and is frequently encountered in human dwellings, including bathrooms and showers.
Philodromus spectabilis
Philodromus spectabilis is a running crab spider in the family Philodromidae, distributed across the United States and Canada. As a member of this family, it exhibits the characteristic laterigrade leg posture that enables sideways movement. The species has been documented in multiple Canadian provinces including Alberta, Manitoba, and Saskatchewan, as well as throughout the United States. It is one of many Philodromus species that occasionally enters human dwellings and has been observed in indoor environments such as bathrooms.
Physocyclus californicus
A cellar spider species in the family Pholcidae, distributed across the southwestern United States and Mexico. Adults are active during fall months, with males wandering in search of mates. The species frequently occurs in human dwellings, where it constructs webs in ceiling corners and other sheltered locations.
Reduvius personatus
Masked Hunter
Reduvius personatus, commonly known as the masked hunter, is a cosmopolitan assassin bug recognized for the distinctive debris-camouflaged appearance of its nymphs. The species is a generalist predator of small arthropods and has been introduced to multiple continents through human activity. Adults are uniformly dark brown to black, winged insects measuring 17–22 mm, while nymphs appear gray or light-colored due to accumulated dust and lint on their bodies. Though beneficial as predators of household pests like bed bugs, they can deliver a painful defensive bite when mishandled.
Supella
brown-banded cockroaches
Supella is a genus of small, synanthropic cockroaches in the family Ectobiidae, with the brown-banded cockroach (S. longipalpa) being the most widespread and well-known species. Native to Africa and the Arabian Peninsula, the genus has achieved cosmopolitan distribution through human-mediated transport. Members of this genus are distinguished by transverse pale bands across the wings and abdomen, pronounced sexual dimorphism in wing development, and a preference for warm, dry indoor environments. The type species S. longipalpa is a significant public health pest that completes its entire life cycle within human-built structures.
Trachelas pacificus
Bull-headed sac spider
Trachelas pacificus is a species of true spider in the family Trachelidae, distributed across the southwestern United States and northwestern Mexico. It is commonly found in houses and adults are present year-round. The species is part of a genus known for sac-like retreats and active hunting behavior rather than web-building.
Trachelas tranquillus
Broad-faced Sac Spider, Ground Sac Spider
Trachelas tranquillus, commonly known as the broad-faced sac spider, is a hunting spider native to eastern North America. This species is frequently encountered indoors during autumn when males wander in search of mates. It does not construct webs for prey capture but instead hunts actively at night, often around porch lights where insects congregate. Once considered mildly venomous to humans, it is now classified as harmless, though rare bites can cause localized pain and swelling.