Evarcha arcuata is a species of jumping spider

Jumping spider

The jumping spider family contains more than 500 described genera and about 5,000 described species, making it the largest family of spiders with about 13% of all species. Jumping spiders have some of the best vision among invertebrates and use it in courtship, hunting and navigation...

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Description

Males reach a body length of about six, females up to eight millimetres. The female has a brown and whitish cephalothorax

Cephalothorax

The cephalothorax is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. The word cephalothorax is derived from the Greek words for head and thorax...

, and an opisthosoma

Opisthosoma

The opisthosoma is the posterior part of the body in some arthropods, behind the prosoma . It is a distinctive feature of the subphylum Chelicerata...

 with a distinct pattern of black diagonal spots, sometimes with a white outline.
The male is in contrast almost black with a copper-like gloss. His face features a horizontal pattern of black and white stripes. While males are found very frequently, females often hide in their retreats, for example between rolled leaves. During early winter he guards his egg sac here.

Name

The species name is possibly derived from Latin

Latin

Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

arcus "bow", with the meaning "arched", referring to the arched abdomen.