Length 2-3mm. Prosoma light brown. Opisthosoma grey.

"Requires examination at high magnification in good lighting, typically examination of the genitalia." Bee, L., Oxford, G., & Smith, H. (2020). Britain's Spiders: A Field Guide. Second Edition. Princeton University Press.

Heath and moorland, also post-industrial sites. Found in ants nests, usually under embedded rocks. 

Spring-Autumn.

Fragmented and possibly declining populations. Mostly north and west Britain. 

Uncommon. 

https://srs.britishspiders.org.uk/portal.php/p/Summary/s/Evansia+merens