Decumbent -ous: sloping gradually downward.
Decrepitans: crackling.
Decumbent: bending down at tip from an upright base.
Decurrent: closely attached to and running down another body.
Decurved: bowed downward.
Decussate: crossing at an angle: X-like: in cross pairs; or, when bristles alternately cross each other, as in some Diptera.
Deflected: bent downward: the wings, when the inner margins lap and the outer edges decline toward the sides.
Deflexed: abruptly bent downward.
Deformed: twisted or set in an unusual form: specifically, in Coleoptera applied to knotted or twisted antennae as in male Meloids.
Dehiscence: the splitting of the pupal integument in the emergence of the adult in Lepidoptera.