acrida chinensis
蟿 refers to a specific insect, Acrida chinensis, a type of grasshopper. Its meaning is narrow and does not extend to broader concepts.
蟿 is a phono-semantic compound: 虫 (insect) provides the meaning, and 毄 (ケイ) likely contributes the sound. The exact historical development of the character is uncertain.
The insect radical 虫 at the bottom marks this as a bug. The complex upper part 毄 can be imagined as a grasshopper's long legs and segmented body, making 蟿 the specific grasshopper Acrida chinensis.
For ケイ, picture a grasshopper leaping onto a cake: cake -> ケイ, and the insect lands right on top.
—