Setaceous

Setaceous antennae are bristle-shaped, and tapered from the base to the tip.
Setaceous antennae are bristle-shaped, and tapered from the base to the tip. Wikimedia Commons user L. Shyamal, license cc-by-SA 2.5

Definition:

Setaceous is a term used to describe certain insect antennae. The term comes from the Latin seta, meaning bristle. Setaceous antennae are bristle-shaped, and tapered from the base to the tip.

Examples of insects with setaceous antennae include:

Setaceous is just one of many morphological forms of insect antennae. See also:

Source: Borror and DeLong's Introduction to the Study of Insects, 7th Edition, by Charles A. Triplehorn and Norman F. Johnson