Ooctonus vulgatus is a tiny (1.5-2mm) parasitoid wasp, one of the large family of Fairy Wasps (Mymaridae) characterized by the following unique combination of features: 

• Posterior scutellum mostly smooth except for a weak, often inconspicuous sculpture at lateral borders and sometimes also at anterior margin
• propodeum with median carina absent or very short (relatively longer in very large specimens), thus the median areole large, extending or almost extending to anterior margin of propodeum
• petiole short, 0.9–1.2x as long as metacoxa. 

Very similar to O. silvensis, which has F2 of the female antenna notably shorter than F1 and about as long or slightly shorter than F3, and also generally darker legs, particularly meso- and metafemora and meso- and metatibiae.

Unless identified by a recognized expert, requires microscopic examination and photos of key ID features. 

Widespread. 

All year. 

A very common parasitoid of the Common Froghopper, Philaenus spumarius.

Common (the most frequently-occurring member of this genus) but rarely recorded due to small size and identification difficulty. 

Unknown.