#simuliidae

Australasian Blackflies

Known as sandflies or namu (in Māori from Proto-Austronesian *ñamuk meaning "mosquito", see also the Malay word nyamuk).

The genus is found in Australia and New Zealand, and some species are infamous bloodsuckers. Consider, for example, this account from 1844.

"…no sooner had the sun risen, and we issued from our tent to wash by the river side, than those peculiarly vexatious pests, the sand-flies (namu), commenced their attacks on our bare hands and feet. The sand-fly is a small black insect, and swarms in such myriads, that one is never free from their vengeance, if remaining for a single instant in the same position: whilst sketching, my hands are frequently covered with blood, and their numbers being inexhaustible, one at last gets weary of killing them.…The horrid sand-flies attacked us to-day more unmercifully than ever, and in such clouds that I should imagine them to be a species very nearly allied to those that constituted the fourth plague of Egypt." —Angas, G. F. (1847) Chapter I: "Journey into the interior of New Zealand — The Waikato". In Savage Life and Scenes in Australia and New Zealand Vol. II.

Only three species in New Zealand attack humans. One is A. australense, which is not in fact found in Australia. As with mosquitos it's the females that need the blood meal before they can lay eggs. I did notice some interesting behaviour on the ones I let bite me at St Arnaud. The would land on my exposed skin, and run around in an apparently confused fashion, until they found the edge of my clothing and duck undernath the hem before they would start to feed. I have to assume that's because mammals were in very short supply until humans arrived on the islands, and they evolved with large birds as prey - the flies were probably trying to find feathers to hide beneath.

There are some 2200 described species of Simuliid worldwide - some are vectors of extremely unpleasant diseases such as River Blindness. Even when they aren't infecting you with nasty parasites, or bacterial infections of the maddeningly itchy wounds, the sheer numbers in some part of the world can make conditions utterly nightmarish.

Black flies attack in the Canadian arctic, Dubawnt River Nunavut. Nicolas Perrault.

Simuliid larvae live in clean running water, attached to rocks with hook on their tails, and catching passing food particles with folding fans around their mouths.