Dominant: a character more constant and conspicuous than any other: a type or series occurring in large numbers both as to genera, species and individuals and in which differentiation is yet active.

Dorsad: extending or directed toward the upper side.

Dorsal: of or belonging to the upper surface: in Diptera, that face of the laterally extended legs visible from above.

Dorsal bristles: see dorso-central.

Dorsal diaphragm: the wings of the heart, or the very thin membrane upon which these muscles rest: = pericardial diaphragm, q.v.

Dorsal gland orifices: in Diaspinae, oval orifices arranged in more or less distinct rows on the surface of the pygidium, through which is discharged the material of which the dorsal scale is formed.

Dorsal glands: see last preceding title.

Dorsal line: in caterpillars, extends longitudinally on the middle of the back or dorsal.

Dorsal scale: that part of the covering scale of the Diaspinae that lies above the insect, as opposed to the ventral scale, which lies below.

Dorsal space: in slug-caterpillars is the area between the sub-dorsal ridges.