People across the Front Range are now seeing the moths, and the residue they leave behind, on windows, driveways and mirrors.
The moth cycle typically begins in March and April on the Great Plains.
Once they hatch, the moths follow the blooming flowers as they move from the plains to the mountains.
The moths usually arrive in the Front Range in May, but drier conditions can lead to moths appearing earlier in the season.
In September, the moths will migrate back to the Eastern Plains to start the whole process over again.