Tex. Code Crim. Proc. art. 34.01
A "special venire" is a writ issued in a capital case by order of the district court, commanding the sheriff to summon either verbally or by mail such a number of persons, not less than 50, as the court may order, to appear before the court on a day named in the writ from whom the jury for the trial of such case is to be selected. Where as many as one hundred jurors have been summoned in such county for regular service for the week in which such capital case is set for trial, the judge of the court having jurisdiction of a capital case in which a motion for a special venire has been made, shall grant or refuse such motion for a special venire, and upon such refusal require the case to be tried by regular jurors summoned for service in such county for the week in which such capital case is set for trial and such additional talesmen as may be summoned by the sheriff upon order of the court as provided in Article 34.02 of this Code, but the clerk of such court shall furnish the defendant or his counsel a list of the persons summoned as provided in Article 34.04.
Tex. Code Crim. Proc. § 34.01