Every member of the National Guard of the Virgin Islands who Guard of the Virgin Islands who fails to report for duty to his Commanding Officer on the date and time prescribed by the Commander-in-Chief to report for duty in the Territorial Active Military Service or for duty other than the Territorial Active Military Service and all persons subject to the provisions of this chapter, who having been duly summoned, fail to appear without a valid cause to justify their nonappearance in the cases as set forth above, shall be deemed as absent without authorization or as deserters from duty.