羆 combines 罒 (a net) with 熊 (bear), likely to specify a type of bear. The exact historical development is uncertain, but the character appears to be a compound built from 熊.
Meaning mnemonic
A bear (熊) caught under a net (罒) — that's a brown bear specifically, as if the net distinguishes it from other bears.
Reading mnemonic
For ヒ, imagine a brown bear letting out a big sigh: hee -> ヒ, as it rests under the net.
