The females have smaller eyes and oviducts in the lower abdomen. Often, many nymphs will then simultaneously let go of their hold on their anchor in the water and float up to the top. Once they reach the air, the cuticle splits open on the thorax and the wings come out. This is the time of greatest vulnerability in their lives as they float on the water before they are strong enough to fly. Once it gains some strength, it flies from the water to some form of shelter such as a tree, long grass, or the underside of a bridge and molts again within 24 to 48 hours.
Thisadditional molt allows the legs and tails of the insect to grow more.
Longer tails give more stability in flight, and longer legs make it easier for the male to grasp the female in mating. The longer legs and tails allow for more rapid flight. The corrugation of the wings protects them by making them more flexible and therefore less vulnerable to wind damage. The imago mates and dies within a few hours to a day. Notice the Baetid has a slender, cylindrical body and small gills on its abdomen.