Femina: the female, or belonging to that sex.
Femorate -us: with abnormal or unusually developed femora or thighs.
Femoro-tibial: pertaining to both femur and tibia or to the articulation between them.
Femur -ora: the thigh: usually the stoutest segment of the leg, articulated to the body through trochanter and coxa and bearing the tibia at its distal end: in Coccidae and quite commonly, the femur and trochanter are considered as one, for measuring purposes.
Fenestra: a window; a transparent glassy spot or mark; a pellucid mark in a vein: a small, pale, membranous area at the base of the antenna in roaches.
Fenestrate: with transparent or window-like naked spots as in the wings of some Lepidoptera.
Fenestrate membrane: of the compound eye is at the base of the ommatidia, at their junction with the optic nerve; see retina.
Ferreous -eus: the metallic gray of polished iron.
Ferrugineous -ous, -eus, -osus: rusty red-brown [Dragon's blood, but brighter].
Ferrugino-testaeeous: a rusty yellow brown: a mixture of rusty red with dull yellow brown.