I read Planet of the Bugs (Chicago, 2014) by Scott Richard Shaw, a Wyoming entomologist. It's a good book on a great topic -- the evolution of insects. In the acknowledgements, Shaw thanks his editor for helping him to "shape a bulky manuscript into a sleeker book" but I think I would have much preferred the fatter unpublished version, which I imagine would have been heavier on lurid, fascinating detail. I think that Shaw's editor may have misunderestimated his enthusiastic readership.
Shaw loves his insects and writes the evolution of life bug-centrically. Instead of the ordinary telling of evolution, where everything leads ineluctably to majestic us, Shaw presents the triumph of the six-legged kind. For example, Shaw disparages our (I mean mankind's) walking and running. "Two-legged bipedal locomotion is so unstable and difficult to master that it seems highly improbable and almost pointless." He has a point there. A child takes a year to learn to walk, and even after he does so, he staggers like a drunken sailor for several months. No other creature on earth is so ungainly at the outset.
Moreover, Shaw adds, six-leggedness optimizes balance and stability and has the potential for rapid motion. "Six legged form is sublime. Fifty million insect species can't possibly be wrong."
If I understand it correctly, most insect species propel themselves by alternately moving one of their two tripods of legs -- and tripods are inherently stable. It's a great system.
Now that I've achieved the "golden years", I spend too much time worrying about crashing to the ground. I don't want to break a hip or a wrist, both of them common afflictions of the two-legged. Nno one has ever seen a beetle trip, or an ant sprawl embarrassingly on the sidewalk.
Too bad we don't have six legs. Or even four (the othe two having evolved into arms). We'd be better off. We'd need two pairs of hips, of course, and copulation would be more complicated, but it would be worth it. Speed, stability, grace. Four legs would definitely be sublime.
On the other hand, I'm glad that we evolved an internal skeleton, which the insects never did. I wouldn't want an exoskeleton or carapace. It would be ungainly, troublesome. And probably accompanied by all sorts of emotional displays. "Don't pay any attention to him. He's moulting."