Three Glasgow Warriors forwards are to join the Scotland squad for the final match of their summer tour against South Africa in Port Elizabeth next Saturday.They are the vastly experienced tight-head prop, Euan Murray and the uncapped back-row forwards Tyrone Holmes and Adam Ashe.Murray, 33, would win his 60th cap should he feature against the country that he toured with the 2009 British & Irish Lions. He re-joined Glasgow Warriors from Worcester earlier this week.Holmes, 28, who played for the Stormers in Super Rugby and was part of the 2012 Western Province Currie Cup winning team, qualifies for Scotland on account of his Peebles born father, Steven.Macphail ScholarAshe, 20, (pictured above) a product of the Hillfoots and Stirling County clubs, and a graduate of Scotland age-grade sides and Scotland 7s, has been playing for Lincoln University in Christchurch, New Zealand, having been awarded the 2014 John Macphail Scholarship. He is another to benefit from the guidance of Iain Monaghan as part of Glasgow's Elite Development programme.Scotland head coach Vern Cotter said: "We're adding to our back-row resources for next week, while, at the same time, trying to give the Commonwealth Games sevens squad as much quality preparation as possible."I'm looking forward to working with Euan, Tyrone and Adam and for the squad to build on what has been achieved so far on our summer tour."With Murray joining the squad in South Africa, Gordon Reid, who has been involved in all three Tests on the tour and played a key part in Glasgow Warriors reaching the PRO12 final last month, will now return home to rest ahead of commencing pre-season club training.The Scotland squad leave Argentina today after last night's 21-19 victory in Cordoba and will undertake four flights before they are due to arrive in Port Elizabeth tomorrow afternoon.