Assertion: grasshopper's wing | /r/HasProperty | front
Facets:
Source sentences:
text: Males "sing" by rubbing their hind legs against their front wings, producing a broadband signal.
text: Most grasshoppers have both front and back wings; the wings on their backs are used for flying.
text: Grasshoppers have wings but their front wings are not used for flight.
text: They make their song by rubbing their wings together or by rubbing their hind legs against their front wings.