I've not looked into subspecies of L. mathura. The last major work on the genus that I have access to is Pogue & Schaefer, 2007, which gives subpallida as the Taiwanese subspecies under the listed synonymy. It may be better for now not to refer to subspecies level populations as there remains much work to investigate the population dynamics of the species.
Pogue, Michael G. and Schaefer, Paul W. (2007): A review of Selected Species of Lymantria Hübner,  (Lepidoptera: Lymantriidae) from Subtropical and Temperate Regions of Asia, including the Descriptions of three new species, some potentially invasive to North America. Forest Health Technology Enterprise Team, USDA Forest Service, Morgantown WV, USA. vii + 223 pp.