a weevil that eats corn or wheat (see Molina); this also supports how the other, similar word ("ocuilto") could be written ocuilton (SW)
Alonso de Molina:
ocuiltontli. gorgojo que come el trigo, o mayz. Alonso de Molina, Vocabulario en lengua castellana y mexicana y mexicana y castellana, 1571, part 2, Nahuatl to Spanish, f. 76r. col. 1. Thanks to Joe Campbell for providing the transcription.