Explanation of Terms Used in Entomology Part 24

Discoidal cell: Hymenoptera (Norton) 1st medial 2, medial 3 and medial 4 (Comst.).

Discoidal field: see discoidal area.

Discoidal nervule: Lepidoptera; = media 1 (Comst.).

Discoidal triangle: Odonata - see triangle.

Discoidal vein: Diptera (Schiner), = media 2 (Comst.) anterior intercalary vein (Loew); Hymenopteran (Norton), = media 2 (Comst.), beyond the junction with the medial cross-vein: Trichoptera; the first and largest branch of the humeral vein.

Discoideous: =discoidal.

Discolored -orous: a different color from the surrounding, more or less contrasting; not concolorous.

Discota: insects in which development of the adults is from imaginal discs: see adiscota.

Discrete: distinctly separated.

Discs: the abdominal motor processes of coleopterous larve.

Discus: a disc; a somewhat flat circular part or area.

Disjoined or Disjointed: see disjunctus.

Disjunct: with head, thorax and abdomen separated by constrictions.

Disjunctus: separated; standing apart.

Disk: the central upper surface of any part; all the area within a margin; the central area of a wing: in Trichoptera, the obliquely ridged outer surface of hind femur in saltatoria.

Dislocated: a stria, band or line interrupted in continuity, when the tips of the interrupted parts are not in a right line with each other.

Disperses: with scattered markings, punctures or other small sculptures.

Disposed: arranged or laid out.

Dissepiment: a part.i.tion wall: applied to the forming septa separating the coelom-sacs in the embryo; also the thin envelope about the members in obtect pupae.

Dissilient: bursting open elastically.

Distad: toward the distal end.

Distal: that part of a joint farthest from the body.

Distant: remote from: standing considerably apart.

Distichous: applied to antennae when lateral processes originate at the apices of the joints and bend forward at acute angles to them.

Distiproboscis: the outer third of the proboscis in Muscid flies, bearing the labella.

Distychus: bipart.i.te: separated into two parts.

Ditrocha: Hymenoptera; that series having the trochanter two-jointed.

Diurnae: day fliers: applied to b.u.t.terflies.

Diurnal: such insects as are active or habitually fly by day only.

Divaricable: able to spread apart or divaricate.

Divaricate: straddling or spreading apart: when the wings are lapped at base and diverge behind: tarsal claws when arising at opposite sides of the joint and separating widely.

Divergent: spreading out from a common base; in Coleoptera, tarsal claws are divergent when they spread out only a little; divaricate when they separate widely.

Diverse: unequal: differing in size or shape: of various kinds.

Diverticulum -la: an oft-shoot from a vessel or from the alimentary ca.n.a.l usually blind or sac-like: applied to the caecal tubes or pouches: any extensions or ev.a.g.i.n.ations of the hypodermic.

Dividens (vena): Trichoptera; 1st a.n.a.l (Comst.).

Dog-ear marks: in bees: small, subtriangular marks of light color, just below the antennae (c.o.c.kerell).

Dolabriform: hatchet-shaped: compressed, with a prominent dilated keel and cylindrical base.

Dolioloides: applied to obtect or coarctate pupae.

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 t.i.tle.

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 s.p.a.ce: in slug-caterpillars is the area between the sub-dorsal ridges.

Dorsal vessel: the heart; q.v.

Dorsi-meson: the middle of the upper surface.