As an adult, "T. pityocampa" has predominantly light brown forewings with brown markings. The moth's hindwings are white. Females have larger wingspans of , compared to a male's . Adults only live for a single day, when they mate and lay eggs. How far they are able to spread depends on how far the female is able to fly during her short time as an adult. Her average flying distance is , with a maximum recorded of . The species flies from May to July.