Cheiracanthium mildei
(Long-legged Sac Spider)

Taxonomic Hierarchy

  • Kingdom: Animalia
  • Phylum: Arthropoda
  • Class: Arachnida
  • Order: Araneae
  • Suborder: Araneomorphae
  • Family: Eutichuridae
  • Genus: Cheiracanthium
  • Species: Cheiracanthium mildei

Common Name (AASMore information icon)

Long-legged Sac Spider

Other Common Names

Sac Spider, Yellow Sac Spider, Black-footed Spider, Prowling Spider, Slender Sac Spider, Yellow House Spider


Ludwig Carl Christian Koch, 1864


ky-ruh-KAN-thee-um MILL-dee-eye

Identification Traits

Disclaimer: The following table provides a quick overview of the spider's basic attributes. The physical traits are greatly generalized in order to aid in the identification and sorting of spider species using our search feature. This information is not exhaustive, and keep in mind that traits such as color, markings, and overall size and shape can vary widely within a species due to variables such as the spider's age, gender, diet, hydration level, climate, and habitat. Though experienced arachnologists and hobbyists can often classify spiders rather accurately based on their unique markings and general appearance, it's important to know that scientifically accurate spider identification relies on detailed taxonomic keys and microscopic examinations of a spider's reproductive organs.

Female iconFemale Male iconMale
Body size More information icon 7mm - 10mm 5mm - 9mm
Eye count 8
Primary Colors
Identifying Traits Patternless, Legs solid color, Especially long legs
Web style Retreat or silken sac

Additional Remarks

  • General appearance almost the same as in the native¬†species Cheiracanthium inclusum; the two should be separated only by microscope exam.
  • Historically, this spider has been implicated in necrotic bites, however, recent research has exonerated the species as a cause of necrotic wounds.
  • Cheiracanthium spiders are sometimes¬†mistaken for brown recluses (Loxosceles reclusa) inside homes.
  • Typically most common inside homes and buildings, while our native North American species,¬†Cheiracanthium inclusum, is found more often outdoors in fields and foliage.
  • The female usually encloses herself inside her egg sac and stands guard over the eggs until the spiderlings emerge.
  • Females probably mate only once, but they can create up to 5 egg sacs in their lifetime.
  • In March 2011, Mazda recalled approximately 50,000 cars (Mazda6) because this species of spider was building its retreats inside of fuel lines. At least that was the publicly-disclosed explanation.

Featured Pictures

Picture of Cheiracanthium mildei (Long-legged Sac Spider) - Dorsal Enlarge picture icon
Picture of Cheiracanthium mildei (Long-legged Sac Spider) - Male - Eyes,Prey Enlarge picture icon
Picture of Cheiracanthium mildei (Long-legged Sac Spider) - Dorsal,Webs Enlarge picture icon
  • Check iconFamily Check iconGenus Check iconSpecies
  • Submitted Calendar iconJun 6, 2016
  • Photographed Picture iconUnknown
  • Copyright icon Louis Lenzini ("elleelle" at
  • SpiderID
    spiderid (Submitted by)
  • Location iconRome, Lazio, Italy
  • Comment icon0 Comments
Picture of Cheiracanthium mildei (Long-legged Sac Spider) - Male - Dorsal Enlarge picture icon
Picture of Cheiracanthium mildei (Long-legged Sac Spider) - Female - Dorsal,Gravid Enlarge picture icon
Picture of Cheiracanthium mildei (Long-legged Sac Spider) - Male - Dorsal Enlarge picture icon
Picture of Cheiracanthium mildei (Long-legged Sac Spider) - Male - Ventral Enlarge picture icon
Picture of Cheiracanthium mildei (Long-legged Sac Spider) - Female - Dorsal Enlarge picture icon
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