I just posted to Instagram (2019/05/18 16:40:22):

Since a few weeks, we have this kinda strange visitor in our rain barrel. It’s a great diving beetle, which happens to be a good swimmer. Today I was finally able to take these photos while he was breathing. These beetles breath through their wing cases by pulling air bubbles through them. I never saw that insect before, and am quite happy to have learned something new, even at my age. #nature #beetle #rainbarrel #greatdivingbeetle #share2steem #neverstoplearning