Arthropods • Earth.com

Northern yellow sac spider

(Cheiracanthium mildei)

galery

Description

Cheiracanthium mildei is a species of spider from the family Cheiracanthiidae. C. mildei is commonly known as the northern yellow sac spider, a name it partially shares with many other spiders of its genus. C. mildei usually has a pale green or tan body, with darker brown palpi and chelicerae. An adult C. mildei is usually 7–10 millimetres (0.3–0.4 in) in body size. Each leg ends in double claws, and the front pair is significantly longer (up to two times the size, however it is clearly shorter than in C. inclusum species). The eyes have a tapetum lucidum that reflects back to the light source once lit, suggesting that the spiders have good to excellent vision and are agile prey hunters. Although this spider can bite humans, the effects appear to be mild. C. mildei is native to Europe and North Africa through to Central Asia. It is introduced to the United States and parts of South America. It widespread across the northeastern United States and eastern Canada, and can be found outside, or more commonly inside houses. It is thought to have been introduced into America from Europe by English colonists. C. mildei is a dominant predator of S. littoralis (a moth species) in Africa and Mid Eastern regions. The mechanism of predation include causing direct death by consuming the larvae and causing indirect death by dispersing larvae from its host plants. Cheiracanthium, commonly called yellow sac spiders, is a genus of araneomorph spiders in the family Cheiracanthiidae, and was first described by Carl Ludwig Koch in 1839. They are usually pale in colour, and have an abdomen that can range from yellow to beige. Both sexes range in size from 5 to 10 millimetres (0.20 to 0.39 in). They are unique among common house spiders because their tarsi do not point either outward, like members of Tegenaria, or inward, like members of Araneus), making them easier to identify. The name is a reference to the backwardly directed process on the cymbium of the male palp. The species epithet is derived from the Greek Ancient Greek: χείρ, romanized: cheir, meaning "hand", and Acanthium, a genus of thorny-stemmed plants. Though they are beneficial predators in agricultural fields, they are also known to be mildly venomous to humans. Painful bites may be incurred from species such as C. punctorium in Europe, C. mildei in Europe and North America, C. inclusum in the Americas, C. lawrencei in South Africa and C. japonicum in Japan.

Taxonomic tree:

Domain:
Kingdom: Animalia
Phylum:
Class:
Order:Araneae
Family:Cheiracanthiidae
Genus:Cheiracanthium
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