Fifth longitudinal vein: Diptera (Will.); = media 3 (Comst.).
Filament: a thread: a long slender process of equal diameter throughout: an elongated appendage.
Filariasis: a disease caused by the presence of minute worms or Filaria, transmitted by mosquitoes. {Scanner's comment: Nowadays it is known that many kinds of filariasis are transmitted by other species of flies, in particular Simuliidae and Tabanidae}
Filate: Diptera; antennae that are simple, without lateral hair or dilation: thread-like.
Filator: the silk spinning structure of caterpillars.
File: the diagonal ridged vein near the base of the tegmina in crickets, used in stridulating: in general any structure wherever situated that serves the same purpose.
Filicornia: insects with thread-like antennae; e.g. in Coleopteran, the Carabidae.
Filiform: thread-like: slender and of equal diameter.
Filippi's glands: a pair of secondary glands, opening into the silk glands of caterpillars near their anterior end.
Fillet: a transverse, raised structure between the antennae in Lepidoptera.
Filose: ending in a thread-like process.
Fimbria: thick, ciliated hair at the termination of any part: fringes.
Fimbriate: a margin or process when set with a fringe of hair closely placed.
Finger: of maxilla, is the digitus, q.v.
First clypeus: see post clypeus.
First inner apical nervure: in Hymenoptera (Nort.); is cubitus 1, from media 4, to first anal (Comst.).
First lateral suture: Odonata; starts from beneath base of front wing behind humeral suture and meets it behind second coxa.
First longitudinal vein: in Diptera; - radius 1 (Comst.).
First submarginal cross-nervure: Hymenoptera; part of the media and the radio-medial cross vein (Comst.).
Fissate: divided or split: with fissures or cracks.
Fissile -is: cleft or divided; as the wings in plume-moths: also used for lamellate.
Fissiparous: applied to that form of asexual generation in which the parent divides; each part becoming a new individual.
Fissure: a crevice: a narrow longitudinal opening: a slit.
Fissus: cleft: longitudinally divided nearly to base.
Fistula: a slender tube: specifically applied to the channel formed by the union of the two parts of proboscis in Lepidoptera.
Fistular: like a slender, cylindrical tube.
Flabellate: with long flat processes folding like a fan.
Flabelliform: fan-shaped.
Explanation of Terms Used in Entomology · The Wunder Library — complete classics, free to read, with narration.