meager profit; petty gain

a metaphor for someone who is rushing around frantically without a clear purpose

to unscrupulously pursue personal gain by any means, like flies swarming around filth

there is no smoke without a fire; rumors or accusations usually have some basis in fact or arise from an individual's own flaws or mistakes

house fly

like flies pursuing a stink; used to describe people flocking toward the rich and powerful or pursuing unsavory and vulgar things

jumping spider (family Salticidae)

a jumping spider (named for its habit of pouncing on houseflies)

Musca (constellation)

fly Amanita or fly agaric (Amanita muscaria)

Venus flytrap (Dionaea muscipula)