Ephydra hians live in the benthic-littoral zone in both soft and hard substrates.
Throughout the summertime, the flies, which live for 3 to 5 days, lay eggs on or under the water's surface.
These hatch in a short time.
The larvae roam the bottom, underwater, feeding on algae and bacteria.
They can remain under the water until they develop into adults.
They do not need to go to the surface to breathe.
They acquire oxygen supplied by photosynthesis of the algae.
Once in the adult stage, the flies are able to walk around and on water, feeding on algae.
They are able to do this thanks to short hairs on their body, which passively trap the surrounding air.
The saline lakes of their habitat is especially wet requiring the fly to have extra hair and special waxes to maintain the air bubble.
Writing in The Washington Post, Ben Guarino noted the flies "must exert forces 18 times their body weight to break through the surface tension of the water".

Ephydra hians are susceptible to changes in temperature.
When the temperature gets colder, their life span prolongs and the individual stages of development take longer.
Adult flies do not lay eggs in the winter months due to the inability to have adequate developmental stages, thus creating a pause in reproduction.
These flies also don't surpass roughly 15 meters deep due to the frigid temperatures and find that temperatures that are closely related to spring and autumn are the most suitable for growth.

You can hold them under water as long as you please--they do not mind it--they are only proud of it.
When you let them go, they pop up to the surface as dry as a patent office report, and walk off as unconcernedly as if they had been educated especially with a view to affording instructive entertainment to man in that particular way.

— Mark Twain, Roughing It 1872
Ephydra hians live in the benthic-littoral zone in both soft and hard substrates. Throughout the summertime, the flies, which live for 3 to 5 days, lay eggs on or under the water's surface. These hatch in a short time. The larvae roam the bottom, underwater, feeding on algae and bacteria. They can remain under the water until they develop into adults. They do not need to go to the surface to breathe. They acquire oxygen supplied by photosynthesis of the algae. Once in the adult stage, the flies are able to walk around and on water, feeding on algae. They are able to do this thanks to short hairs on their body, which passively trap the surrounding air. The saline lakes of their habitat is especially wet requiring the fly to have extra hair and special waxes to maintain the air bubble. Writing in The Washington Post, Ben Guarino noted the flies "must exert forces 18 times their body weight to break through the surface tension of the water".
Ephydra hians are susceptible to changes in temperature. When the temperature gets colder, their life span prolongs and the individual stages of development take longer. Adult flies do not lay eggs in the winter months due to the inability to have adequate developmental stages, thus creating a pause in reproduction. These flies also don't surpass roughly 15 meters deep due to the frigid temperatures and find that temperatures that are closely related to spring and autumn are the most suitable for growth. 
You can hold them under water as long as you please--they do not mind it--they are only proud of it. When you let them go, they pop up to the surface as dry as a patent office report, and walk off as unconcernedly as if they had been educated especially with a view to affording instructive entertainment to man in that particular way.
— Mark Twain, Roughing It 1872
Ephydra hians