In P. trachala hindwing spot 5 (part of the band) juts outwards more than the others; spot 6 is exactly midway between spot 5 & spot 7 (compare P. serina.)
On the forewing there is little overlap(actually none, only the extensions are touching.) between spot 3 (hidden) & spot 4; also hardly any overlap between spot 5 & spot 6 (part of the 3 subapical spots.)
Usually the subapical spots are deeply notched (not in no.2 here.)