actually they do act like a stick silvie...
http://www.brookview.karoo.net/Stick...amouflage.html
its part of thier camoflage. in order to escapr their preditors they act like a stick gently swaying in the breeze so as to blend in with thier background. when a bird (or some other animal) sees it they think 'well nothing there unless i like eating sticks' then move on.
but i do see what you are saying too. they dont call stick insects "browny/grey thin insects", they call them
stick insects cause thats what they look and act like.
and indeed they called this swirling gaseous mass a
galaxy cause thats what
it looks and acts like
