Duple: double, or twice.
Durus: hard.
Dusky: somewhat darkened; pale fuscous.
E: as prefix, is privative and means without.
Ears: organs of hearing, as on the first tibiae or on the first abdominal segment of some Trichoptera.
Ebenine: black like ebony.
Eburneous: ivory white.
Ecalcaratus: without a spur.
Ecaudate: without tails or tail-like processes: usually applied to wings : = excaudate.