Complex sentence: The pinch on the thorax which kills most butterflies is easily withstood, and, apparently only stuns temporarily the butterfly, which quickly recovers and flies out of the net to the utter consternation of the unwary collector.
Split into simpler sentences: The pinch on the thorax which kills most butterflies is easily withstood, and, apparently only stuns the butterfly temporarily. It recovers quickly and flies out of the net to the utter consternation of the unwary collector.