biflabellate

from The Century Dictionary.

• In entomology, having short joints, as an antenna, each provided on two opposite sides with a very long, somewhat flattened process, the processes lying close together, so that the whole organ is somewhat fan-like. It is an extreme modification of the bipectinate type.

from the GNU version of the Collaborative International Dictionary of English.

• adjective (Zoöl.) Flabellate on both sides.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• adjective zoology flabellate on both sides