the solitary wasp
蠃 refers specifically to the solitary wasp, a type of insect. The meaning is narrow and does not extend to broader concepts.
蠃 combines the insect radical 虫 with a phonetic component that is also found in characters like 羸 and 贏. The exact historical development of this phonetic component is uncertain, but it likely contributed the sound while 虫 indicates the wasp meaning.
Inside the complex outer frame, the insect radical 虫 is visible. Picture a solitary wasp building its nest within a tangled, cage-like structure.
For ラ, imagine the solitary wasp buzzing with a low, humming 'ra' sound as it flies: ra -> ラ.