Wyo. Stat. Ann. § 2-13-104

Where two (2) or more beneficiaries are designated to take successively by reason of survivorship under another person's disposition of property and there is no sufficient evidence that these beneficiaries have died otherwise than simultaneously the property thus disposed of shall be divided into as many equal portions as there are successively beneficiaries and those portions shall be distributed respectively to those who would have taken in the event that each designated beneficiary had survived.