Body length male: 6 to 8 mm, female: 7 to 11 mm. Prosoma dark brown to almost black. Chelicerae dark brown, basally with distinct tubercle. Legs dark brown. Opisthosoma dark brown to almost black, vague folium laterally flanked with silver-white, medially also with silver spots. 

Other Tetragnatha species. 

Confirmation of this species requires examination at high magnification in good lighting, typically examination of the genitalia.

On trees and bushes in damp woodland, often near water.

Summer- Autumn.

Widespread but local across England and Wales.

Uncommon in Leicestershire and Rutland.

https://srs.britishspiders.org.uk/portal.php/p/Summary/s/Tetragnatha+nigrita