The woman was entering America from Mexico when she was stopped at a border outpost in Brownsville, Texas.
The live insect - which is studded with gemstones and gold - was fastened to her sweater by a gold chain and safety pin but was able to wander on her jumper.
She declared the live insect to officials and said she had bought it in Mexico as a brooch but it was immediately confiscated by pest control.
Officials refused to allow her to keep the live jewellery because she did not have the correct documents.
Because the woman had declared the insect correctly, she was not handed any fine or penalty.
The beetle was sent to the Plant Inspection Station at Los Indios International Bridge for further identification.
Moving live plant pests in any form into or out of the U.S. has to be declared to customs.
Beetles are a popular subject for jewellery, going back for centuries. It is thought to be relatively common in Mexico for live ones to be decorated in this way.
Jackie Kennedy was rumoured to have been given a living brooch when she was America's first lady.