Sentence:  Blue <WSD>skippers</WSD> in sunny hours ope and shut / Where wormwood and grunsel flowers by the cart ruts ... 
Meaning of the word marked with <WSD> tags:  Any of various butterflies of the families Hesperiidae and its subfamily Megathyminae, having a hairy mothlike body, hooked tips on the antennae, and a darting flight pattern.