At 200 μm (1⁄5 mm; 1⁄125 inch) in length, it is the third-smallest extant insect,[1] comparable in size to some single-celled organisms.

It has a highly reduced nervous system, containing only 7,400 neurons, several orders of magnitude fewer than in larger insects (for example, a honey bee has about 850,000).

Accompanying this shrinkage of brain volume is a shrinking of the occipital area of the head, with the cuticle folding into helical spirals.

[2] Researchers believe the wasp can survive without nuclei because of its short lifespan; the proteins manufactured during the pupal stage last the animal long enough to complete its life journey.

[4] Despite their reduced nervous systems, adult wasps can fly, feed, and locate hosts to lay their eggs.