White-Marked Tussock Moth: the females of this species are essentially wingless, and they have plump, grub-like bodies that are covered in fuzz
Orgyia leucostigma, commonly known as the white-marked tussock moth, is one of the few known examples of a flightless moth. The females of this species are brachypterous, which means that they have tiny, vestigial wings that are completely non-functional; in fact, their wings are barely even visible at all.
Above: close-up of a female white-marked tussock moth
As this article describes:
The adult form of Orgyia leucostigma exhibits strong sexual dimorphism. The males are small, grayish-brown moths with a wingspan of about 25-35 mm. They have feathered antennae that they use to detect pheromones released by females from a considerable distance.
In contrast, the females are wingless and remain on or near their cocoons after emerging. They are larger than the males and have a plump, cylindrical body covered with dense hairs. Since they are flightless, females rely on releasing pheromones to attract males for mating.
Above: the photo at the top depicts a female white-marked tussock moth, while the photo on the bottom shows a male of the same species
After mating, the females lay their eggs atop the remnants of their own cocoons, then cover them with a frothy substance that quickly hardens to form a protective barrier around the eggs.
Above: Orgyia leucostigma in the process of laying its eggs
According to this article:
The white-marked tussock moth is native to eastern North America and parts of Canada. This species of tussock moth overwinters in the egg stage. Eggs are laid by females in groups of approximately 300 in a white frothy mass on the cocoon from which the female moth emerges.
Above: Orgyia leucostigma
Flightlessness occurs in several other tussock moths of the genus Orgyia; it can also be found in some species of bagworm moth (family Psychidae) and footman moth (subfamily Arctiinae).
Above: these photos show female clouded footman moths, Anestia ombrophanes, which are also flightless/wingless
Sources & More Info:
North Carolina State University: White-Marked Tussock Moth Factsheet
UMass Amherst: Orgyia leucostigma
iNaturalist: Photos of White-Marked Tussock Moths
Ohio State University: Sneaky White-Marked Tussock Moth Caterpillars
Ozark Bill: Orgyia leucostigma
Natural Resources Canada: White-Marked Tussock Moth
