Wyo. Stat. § 38-1-101
A person bound as surety in a written instrument for the payment of money, or other valuable thing, may, if right of action accrues thereon, require his creditor by a notice in writing, to commence an action on such instrument forthwith, against the principal debtor; and unless the creditor commences such action within a reasonable time thereafter, and proceed with due diligence, in the ordinary course of law, to recover judgment against the principal debtor for the money or other valuable thing due thereby, and to make by execution the amount thereof, the creditor, or the assignee of such instrument so failing to comply with the requisition of such surety shall thereby forfeit the right which he would otherwise have to demand, and receive of such surety, the amount due thereon.
W.S. 38-1-101