Psilogramma increta
Forewing upperside uniform grey, with the transverse lines more or less obliterated; a black oblique bar at the apex of the discal cell; the apical lines, the costal part of the discal lines, and 2 discal streaks all very conspicuous against the pale background.
Sambath (2014) (STI 20917) illustrated a "grey" Psilogramma species (as Psilogramma menephron menephron) from Dalma Wildlife Sanctuary, Jharkhand; it is unclear whether this is Psilogramma increta or Psilogramma vates and is not mapped here.
An image of a prepupa is posted at http://www.guaminsects.net/uogces/kbwiki/index.php?title=Hornworm_on_Xan... (accessed via http://www.pestnet.org/SummariesofMessages/Crops/Rootstubers/Xanthosomas...) is certainly a Psilogramma species, but whether it is Psilogramma increta or some other species remains to be determined; it is not mapped here. The image appears to be no longer available at the URL cited.