gadfly, horsefly
虻 centers on a biting, blood-sucking fly that pesters livestock and people: a gadfly or horsefly.
虻 combines 虫 (insect) with 亡, which likely contributes a sound element. The character specifically denotes a biting fly.
The insect radical 虫 on the left tells you it's a bug, and the right side 亡 looks like a person lying down, perhaps after being bitten. Imagine a gadfly that bites so hard it knocks you flat.
For ボウ, picture a bow-shaped horsefly buzzing around: bow -> ボウ, and the insect's curved flight path reminds you of the reading.
horsefly; gadfly
bee fly (any insect of family Bombyliidae)
robber fly (Promachus yesonicus)
soldier fly (any fly of family Stratiomyidae, esp. species Stratiomys japonica)
Tabanus trigonus (species of horsefly)
deerfly (Chrysops suavis)
hoverfly (Syrphidae spp.); syrphid
robber fly (any fly of family Asilidae)
horsefly and bee; horsefly and wasp
attempting two tasks at the same time, accomplishing neither; falling between two stools; catching neither the horsefly nor the bee
Tabanus chrysurus (species of horsefly)
horse botfly