Cheiracanthium punctorium, one of several species commonly known as the yellow sac spider, is a spider found from central Europe to Central Asia. They reach a length of about 15 mm, and their bite can penetrate human skin; the bite has been compared to a wasp sting, perhaps a bit more severe, although susceptible persons can have stronger reactions, like nausea.^[1] Females build an egg sac of about 4 cm in high grass. It opens below and is aggressively defended.

Cheiracanthium punctorium
Female Cheiracanthium punctorium
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Subphylum:	Chelicerata
Class:	Arachnida
Order:	Araneae
Infraorder:	Araneomorphae
Family:	Cheiracanthiidae
Genus:	Cheiracanthium
Species:	C. punctorium
Binomial name
Cheiracanthium punctorium (Villers, 1789)
Synonyms
Aranea punctoria Aranea nutrix Clubiona nutrix Cheiracanthium nutrix Drassus maxillosus Anyphaena nutrix Cheiracanthium italicum

In Germany, where it is the only "seriously" venomous spider, it is a rare species, only known to occur in notable numbers in the Kaiserstuhl region, the hottest part of the country. Due to changing weather patterns, leading to increased aridity and less precipitation in some areas, this species spreads to more northern parts of Europe, e.g. Brandenburg, Germany, where the present trend is towards a climate more similar to the Central Asian steppes where C. punctorium is most numerous.

The genus Cheiracanthium was transferred from the Clubionidae to the Miturgidae,^[2] and then to the Cheiracanthiidae.^[3]