Soares & da Silva Motta (2002) explicitly compared the habitus and male genitalia of Xylophanes pearsoni with Xylophanes aglaor, noting in passing that it also differed from Xylophanes loelia. However, the habitus photographs and genitalia drawings in the original description clearly show that Xylophanes pearsoni is actually very close to Xylophanes libya, with which it is compared here.
Male: forewing length: 35 mm. Extremely similar to Xylophanes libya. Forewing upperside as Xylophanes libya but pattern much more uniform, postmedial lines weaker, fourth postmedial line indicated by a very fine line joining a row of vein dots; black subapical spot conspicuous. Forewing underside as Xylophanes libya but first postmedial line continuous. Hindwing upperside as Xylophanes libya but medial band barely extending apically beyond M1 and partially divided into separate spots by the black scaling extending distad along the veins, especially M3 and CuA1 (thus resembling a more extreme version of the pattern seen in Xylophanes loelia).
Female: forewing length: 36 mm. Similar to the male but with broader and more rounded forewings. Forewing upperside similar to that of the male but pattern more contrasting, subbasal and postmedial lines more conspicuous, especially the first postmedial line apical of M3 and the third postmedial line along its entire, rather sinuate, length. Hindwing upperside similar to that of the male but the median band broader and not interrupted by the black scaling extending distad along the veins.
Male genitalia: as Xylophanes libya but left lobe of phallus process with more teeth arranged in a slightly shorter and broader band, and a right lobe with a submarginal as well as a marginal row of teeth.
Moths listed as Xylophanes libya by Duarte Jr & Schlindwein (2005a, b) (nid: 17631 & 17632) from Pernambuco are likely to be Xylophanes pearsoni but this remains to be confirmed.