Eratigena

Eratigena can be distinguished from Malthonica by un-notched trochanters on legs III and IV (notched in Malthonica). It differs from Tegenaria in having six or more teeth on the rear margin of the chelicerae, with teeth closer to the body being smaller; Tegenaria has three to six large teeth of roughly equal size. Within the genus, species of the E. atrica group (E. atrica, E. duellica, E. saeva) are morphologically identical in overall appearance and require examination of palp and epigyne structures for separation.

Medium to large spiders with body lengths of 10–16 mm in adults. Carapace bears two symmetrical dark dorsal bands, which may be serrated or reduced to three or four conspicuous triangles. Plumose (feathery) hairs present on carapace, legs, and opisthosoma. Eye rows are only slightly curved. Abdomen displays paler patches that form anterior-facing chevrons toward the rear. Mature females have legs approximately twice their body length; males have legs roughly three times their body length.

Frequently associated with human habitation, building webs in and around dwellings. Also thrives in natural settings under stones and logs, in tree cavities, and beneath overhanging earth banks.

Native to Europe and Central Asia; introduced and established in North America. Core populations in Britain centered in Newcastle upon Tyne area and Perth/Dundee region of eastern Scotland.

Mature adults appear in August and September. Spiderling emergence timing varies by species: E. atrica emerges in fall, E. agrestis in spring.

Overwinters as half-grown juveniles. Matures the following August/September. Mating occurs in the female's web. Females overwinter with stored sperm and commence laying egg sacs in spring, each containing 60–80 eggs. Males live approximately 18 months; females typically two years or more, with some surviving a third winter.

Constructs funnel-shaped webs. Males may cohabit briefly in the female's web after mating. Sudden appearance of mature spiders during late summer and autumn frequently noted by homeowners.

Frequently encountered in human dwellings due to synanthropic habits. E. agrestis (hobo spider) has been the subject of medical concern in North America, though the validity of its venomous reputation remains disputed. E. atrica (giant house spider) is notable for its large size and rapid movements, often causing alarm despite being generally harmless.

• TegenariaHistorically contained species now placed in Eratigena; differs in having three to six large, equal-sized teeth on rear margin of chelicerae versus six or more teeth of unequal size in Eratigena
• MalthonicaAlso historically contained Eratigena species; differs in having notched trochanters on legs III and IV versus un-notched in Eratigena
• AterigenaAnother anagram-derived genus from Tegenaria; phylogenetically related but morphologically distinct based on established generic characters

Eratigena agrestis has been widely reputed as a medically significant spider in North America (the 'hobo spider'), but this characterization lacks robust scientific support and is considered questionable by arachnological authorities.

• BugGuide
• Wikipedia
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Catalogue of Life
• Life-history data for the funnel weavers Eratigena agrestis and Eratigena atrica (Araneae: Agelenidae) in the Pacific Northwest of North America
• The genome sequence of the house spider, Eratigena atrica (C.L.Koch, 1843) (Araneae: Agelenidae).