Aquatic and Semiaquatic True Bugs
The key for Ephemeroptera can be found in Chapter 4 of the Guide to Aquatic Invertebrates of the Upper Midwest, pages 49-62. Once you have keyed out your insect, you can use the photographs on this website to verify your identification. If you click on the link to each family on the right, you will be directed to a page that has photographs of that family along with close-up photos of their identifying character. The character featured matches the character used in the identification key.
Most aquatic Hemiptera do not rely heavily on dissolved oxygen in the water, but instead obtain oxygen from the atmosphere. Due to their ability ot utilize atmospheric oxygen, Hemiptera are often able to exist in water bodies with low levels of dissolved oxygen.
Most aquatic and semiaquatic Hemiptera are predatory. After grasping a prey item, these predatory hemipterans inject enzymes into the prey with their beaks, first to poison and then to digest the insides of their prey. The softened internal structures are then sucked up through the beak. Some species of these Hemiptera can inflict a painful bite in self-defense when handled.