It is widespread around the world, with species found essentially everywhere except the polar regions and some remote islands.

They are not very diverse in East and Southeast Asia,[11] or in Africa[12][13] Tachydromia are minute, slender flies of shining jet-black color, that are almost devoid of hairs and bristles.

The vertical, rigid proboscis is shorter than the head.

The slender legs bear microscopic hairs, but no bristles.

The males of some species have small spines on the middle femora or tibiae beneath.