Mastigusa diversa

Body length 3 to 3.5 mm. Prosoma light yellow-brown. Sternum yellow-brown. Legs yellow-brown. Opisthosoma light yellowish, sometimes with vague brownish or blackish pattern. Male palps highly distinctive. In natural light females have metallic blue iridescence on the femurs and also have a double row of spines on the underside of the front tibiae. These two features can be seen with a hand-lens. 

Cicurina cicur (similar appearance but does not have metallic blue iridescence on the femurs). 

Good quality photos of males showing unique structure of palps required. Females are difficult to identify and may require microscopic examination. 

This spider has a strong association with ant nests, occasionally found under the bark and in the hollow trunks of dead and ancient trees. 

All year.

National Rarity Status; Vulnerable (VU) JNCC Red List.

Known mostly from a few sites in the Charnwood area. 

https://srs.britishspiders.org.uk/portal.php/p/Summary/s/Mastigusa+macrophthalma