False Black Widow, Cupboard Spider, Bitten Bullet Spider, Dark Comb-Footed Spider
Steatoda grossa
Theridiidae (Cobweb Spiders), Order Araneae. Characterized by a comb of serrated bristles on the tarsus of the fourth leg.
Physical Description
A bulbous, glossy spider with a large, rounded abdomen and a smaller cephalothorax. The exoskeleton has a smooth, satin-like texture without significant hair. Females are much larger and more robust than males.
Size Estimate
Body length 6-11mm for females; leg span 20-30mm. Males are smaller at 4-6mm. This specimen appears to be an adult or sub-adult female.
Coloration & Markings
Dark purple-brown to nearly black base coloration. Typically features a pale, crescent-shaped band on the anterior of the abdomen and sometimes a series of faint spots or chevrons along the dorsal midline.
Web Type
Tangle web or cobweb. A messy, three-dimensional scaffold of sticky silk usually built in corners or crevices near the ground.
Eye Arrangement
Eight eyes in two rows of four. The arrangement is typical of Theridiids, focused on detecting vibrations rather than sharp visual acuity.
Leg Characteristics
Long, slender legs, typically reddish-brown to dark brown. They lack the heavy spination seen in many other spider families and feature a distinct 'comb' on the fourth pair of legs.
Venom & Safety Information
Venom Information
Neurotoxic venom similar in type but much lower in potency than true Latrodectus (Widow) species. Not considered life-threatening.
Medical Significance
Low. Bites cause localized pain, redness, and occasional blistering or mild nausea (steatodism). Symptoms usually resolve within 1-2 days without medical intervention.
Safety Recommendations
If relocation is desired, use the cup-and-paper method. Wear gloves when cleaning dark areas of garages or basements to avoid accidental pinching.
Habitat & Behavior
Habitat & Range
Cosmopolitan distribution worldwide. Primarily found in and around human structures, such as basements, crawlspaces, garages, and behind furniture.
Behavior & Temperament
Sedentary, nocturnal, and extremely shy. They prefer to retreat into crevices when disturbed and are non-aggressive toward humans unless squeezed or handled.
Diet & Prey
Generalist predator of crawling insects, pillbugs, and even other spiders (including true Black Widows). They use sticky silk to entangle prey before biting.
Seasonal Activity
Active year-round in temperature-controlled indoor environments. Outdoor populations peak in late summer and autumn.
Description
The False Black Widow is a frequent indoor resident often mistaken for its more dangerous namesake. It is a master of corners, spending its life upside-down in a tangle of silk, quietly managing household pests. Its glossy, dark appearance gives it an air of mystery, but it is a docile and beneficial roommate in most homes.
Key Features
Glossy rounded abdomen, absence of a red hourglass marking, pale crescent band on the front of the abdomen, and reddish-brown leg joints.
Similar Species
Latrodectus mactans (Black Widow) which has a red hourglass; Steatoda nobilis (Noble False Widow) which has more distinct 'skull' markings; Steatoda borealis.
Life Cycle
Females produce round, white-to-cream silk egg sacs containing 40-100 eggs. They can live up to 6 years, which is unusually long for a small spider.
Ecological Importance
Highly effective at pest control within homes, preying on woodlice, silverfish, and cockroaches that other spiders might avoid.
Conservation Status
Not evaluated by IUCN, but populations are stable and widespread due to their adaptation to human environments.
Interesting Facts
They are known predators of Redback and Black Widow spiders, effectively outcompeting them in urban environments. Their name 'Bitten Bullet' comes from the localized pain of their bite resembling a gunshot wound in older folklore.
Photography Tips
Focus on the dorsal side of the abdomen to capture the crescent marking. Use a side-view or underside shot to confirm the absence of an hourglass if distinguishing from a Black Widow.
Identified: 2026-06-21T15:06:45.453001