Some species maintain their wax-making glands into adulthood, but others don't. Females of many species, however, produce wax to protect their eggs.
Since they're immature, planthopper nymphs are super tiny, as seen in this comparison to a human fingertip.
This is what an adult planthopper looks like if it hangs onto its wax-making abilities. Unfortunately, planthoppers are often vectors for plant diseases.