Backswimmer from Ireland

Subject:  What’s that bug?
Geographic location of the bug:  Dublin, Ireland
Date: 08/03/2018
Time: 01:04 PM EDT
Your letter to the bugman:  Hi, I just found the attached on my kitchen floor and I was wondering if you could identify it please? I think it may have dropped onto the floor from an open Velux window directly above. I currently have it under a  large upturned glass.
It does have wings and occasionally tries to fly. It’s about 2 – 3 cm long. The rear legs are markedly longer and wider than its other limbs.
The temperature here is currently 25 Celcius, in case that matters?
Many thanks for any information you can give me!
Kind regards,
How you want your letter signed:  Mark Walsh

Dear Mark,
This is an aquatic True Bug commonly called a Backswimmer, and like many aquatic True Bugs, it can fly quite well, an adaptation that is quite helpful in the event a pond or swamp it is living in happens to dry out.  Based on images posted to Nature Spot, it appears it is the Common Backswimmer, Notonecta glauca, and the site states:  “Up to nearly 2 cm in size, and commonly called backswimmers because they swim upside down and are often seen at the surface of the water. Notonecta glauca is light brown in colour with a number of dark markings and large reddish eyes. It often looks silvery as air becomes trapped in a layer of bristles covering the lower surface. The powerful oar-like hind legs are modified for swimming; they are long, flattened and fringed with hairs”  The site also states:  “Backswimmers are predators that attack prey as large as tadpoles and small fish, the forelegs, which are short and strong, are used for grabbing prey.”  Like other predatory True Bugs, they have mouths adapted to piercing and sucking fluids from prey, but they are also capable of biting unwary swimmers, leading to common names like Water Bees or Water Wasps, according to the North American site BugGuide which also notes:  “Come to lights; may invade swimming pools and become a nuisance.”  According to UK Safari:  “Adult Backswimmers are able to fly.  They hunt their prey by floating motionless on the water surface.  When they detect movement in the water they swim towards it to see if it is worth catching.  The bite from a Backswimmer can be painful as their saliva is toxic.”