Flagellum: that part of the antenna beyond the pedicel: a whip or whip-like process: the tail-like process of a spermatozoön.
Flammate -eus: flaming or fiery red [vermilion intensified].
Flange: a projecting rim or edge.
Flank: the sides of the thorax: the pleura.
Flaring: widening out like the mouth of a trumpet.
Flavescent: somewhat yellow.
Flavid: yellowed: sulphur yellow.
Flavo-testaceous: light yellow-brown: almost luteous.
Flavous -us: sulphur yellow [gamboge].
Flavo-vixens: green verging upon yellow [apple green + chrome yellow].