kind of cicada
螗 refers to a specific kind of cicada. The meaning is narrow and concrete, centered on this insect.
螗 combines 虫 (insect) with 唐, which likely provides the sound. The character was created to name a particular cicada species.
The insect radical 虫 on the left tells you it's a bug, and the right side 唐 suggests the sound. Picture a cicada buzzing loudly in a Tang dynasty garden.
For トウ, imagine a cicada landing on your big toe: toe -> トウ, and the insect sits there singing.