[3] C. erraticum is a distinctively marked spider which shows a wide dark red stripe running down the centre of the abdomen, which is in turn surrounded by an area of creamy-yellow while the head is a reddish brown.

[4] The species has a Palearctic distribution, from Ireland to east Asia.

[5] In Britain the altitudinal range is from sea level to 700 m.[5] In early summer C. erraticum builds a retreat made from two or three leaves or grass heads which are stitched together to hold the female and her egg sac.

Later in the year, the immature spiders, which are already showing the reddish median stripe on the abdomen, can be found in small silk cells on plant stems.

[5] The spider wasp Homonotus sanguinolentus is a rare species which is wholly dependent on Cheiracanthium spiders and in Britain is wholly dependent on C. erraticum.