The appearance of Phyllium ericoriai "Quezon" varies significantly depending on the insect’s sex and developmental stage.
Nymphs: Newly hatched nymphs are dark black in colour with reddish and orange highlights. They are fairly large compared to closely related species, measuring ~15 mm in length and ~7–8 mm in width. These nymphs strongly resemble large ants in appearance. After several weeks of feeding, they begin to develop the green coloration associated with this species.
Females: Adult females of Phyllium ericoriai "Quezon" have flattened, irregular bodies with round abdomens. They feature enlarged forelegs and are predominantly green in colour with red lines adorning their body edges at adulthood, although they can also display shades of yellow and brown. Females are medium in size, ranging from ~75–90 mm in length. They have large, broad, non-functional forewings that cover almost the entire abdomen. Two short antennae, orange in colour, are longer than in other species, each measuring about 7 mm in length.
Males: Adult males of Phyllium ericoriai "Quezon" are slimmer and smaller than females, reaching approximately 60–65 mm in length. They have a spoon-shaped abdomen and are predominantly green in colour, with brown markings along their legs and body edges. Males possess fully functional wings that enable flight. Their antennae are notably longer than those of females, measuring ~55 mm in length.