At the recreational lake where I was planning to swim, the beetle in the picture above suddenly emerged from the sandy bottom. It briefly took in air at the surface and then quickly swam back down, kicking its hind legs, to disappear into the bottom. Only the air bubble on its abdomen was sticking out above the sand. It looked like a Dytiscus species, but Dytiscidae swim with both hind legs simultaneously. I retrieved an empty jam jar from the car and pressed it around the air bubble, as deep into the sand as possible. This allowed me to capture the beetle, and I took it home for a few slides and identification.

I didn't have a good water beetle book yet, and at first I couldn't identify this specimen, with its strangely spherical body and bulging eyes. It was a very shy model, just trying to hide. This became clear a few years later, when a male specimen was photographed on a slightly deeper sandy bottom. But while photographing this female specimen on that quiet evening, I was startled by the sudden sounds this beetle made.

Then I remembered that in one of my English books, there was something about a "Screech Beetle." And there I finally found the beetle as Pelobius Hermanni, an older name for this beetle. (More about the name: on the first page under "What's in a name.")

With the beetle being so shy, it wasn't easy to make a decent slide, especially from above. In the image at the top of this page, the beetle is partially floating on the water. Below is a less-than-sharp image.

With its large pointed jaws this beetle catches its prey, mainly Chironomid larvae and small worms.

This paragraph is my interpretation of what Balfour-Browne (1922) wrote: Squeak beetles hibernate from November to March in the mud, with their legs and antennae folded against their bodies. From late March to mid-June, the females lay eight to ten eggs on an aquatic plant, in a jelly string that expands after laying. Balfour-Browne observed no more than twenty eggs per beetle. After 25 to 10 days, depending on the temperature, the larvae hatch.

Finally, below is a picture that clearly shows the strangely rounded shape of this beetle.

Literature: See the list on the first page.