Guardian Nature School Team Contact Blog Project Noah Facebook Project Noah Twitter

A global community of nature enthusiasts
photographing and learning about wildlife

Join Project Noah!
nature school apple icon

Project Noah Nature School visit nature school

Water measurer

Hydrometra spp.


Hydrometrid bugs are of a greyish or pale brown color, and relatively large amongst Gerromorpha at around 8 mm, although some can exceed 15 mm. Their body and legs are long and slender, to the point where they resemble tiny phasmatodeans. The family is mostly wingless, but winged forms do occur. The head is long as well, usually more so than the body. Their eyes are located a little behind the middle of the head and tend to bulge. Their antennae, positioned at the end of its head are four-segmented and their tarsi three-segmented . (information from Wikipedia)


Found on the edges of ponds either on aquatic vegetation or walking slowly over the surface of the water.


North America has 9 species. Also known as "marsh treader." This marks the first time I've ever seen this animal. I'm sure I glanced at the entry in my insect field guide, but since I had never seen one, I glossed over it. I love seeing new animals and this little creature has made my week so much better. I just wish they were a bit easier to photograph! The average body length on these was about 10-12 mm.

Species ID Suggestions

Sign in to suggest organism ID


Hema  Shah
Hema Shah 11 years ago


oxyjack 11 years ago

Good Eye! I love these little guys.

Spotted by

Tulsa, Oklahoma, USA

Spotted on May 8, 2012
Submitted on May 9, 2012

Related Spottings

Water Measurer Spotting Water Measurer Water Boatman Beetle

Nearby Spottings

Dark-Eyed ("Slate-Colored") Junco European Starling Northern Cardinal American Robin
Noah Guardians
Noah Sponsors
join Project Noah Team

Join the Project Noah Team