Explanation of Terms Used in Entomology Part 23

Dichoptic: Diptera; eyes separated by front: not contiguous: see holoptic.

Dichotomous: forked: dividing by pairs.

Dichromatism: the possession of two color varieties.

Dictyoptera: an ordinal term applied to the roaches: also more generally, to the Orthoptera. {Scanner's comment: Roaches are now cla.s.sed as Dictyoptera, and Orthoptera are now cla.s.sed as distinct from Dictyoptera}

Didactyle -us: two-toed: with two tarsi of equal length.

Didymus: double: geminate.

Difformis: irregular in form or outline: not comparable; anomalous.

Diffracted: bending in different directions.

Diffuse: spreading out; without distinct edge or margin.

Digestive tract: the alimentary ca.n.a.l as a whole: more specifically that portion behind the crop, in which a.s.similation takes place.

Digitate: finger-like, or divided into finger-like processes.

Digitiform: formed, shaped like or having the function of a finger.

Digitules: appendages on the feet of Coccidae; in Lecanium, four k.n.o.bbed hairs.

Digitus: the terminal joint of the tarsus, bearing the claws: a small appendage attached to the lacinia of the maxilla; rarely present and probably tactile.

Digoneutism: the power to produce two broods in one season.

Dilatatus: Coleoptera a margin, when the sharp marginal edge extends beyond its usual limit: the base when the transverse diameter is much longer at one part.

Dilated: widened, expanded.

Dilation: an expansion or widening.

Dilute: thinned out: applied to color means weak or pale.

Dilution: much thinned out or diluted.

Dimera: forms with two-jointed tarsi: specifically applied to some groups of h.o.m.optera.

Dimerous: having only two tarsal joints.

Dimidiate -us: halved; extending half way around; applied to elytra when they cover only half the abdomen.

Dimidius: of half length.

Dimorphic: occurring in two well-marked forms.

Dimorphism: a difference in form, color, etc, between individuals of the same species, characterizing two distinct types: may be seasonal, s.e.xual or geographic.

Dioecious: with distinct s.e.xes.

Dioptrate: an ocellate spot with the pupil divided by a transverse line.

Dioptric: with a transversely divided ocellus.

Diploglossata: an ordinal term proposed for Hemimeridae, because of the supposed presence of a second l.a.b.i.al segment.

Diplogangliata: applied to the Arthropods.

Diploptera: = diplopteryga; q.v.

Diplopteryga: Hymenoptera; wasps in which the wings are longitudinally folded when at rest.

Dipneumones: having two lungs (certain spiders).

Diptera: an ordinal term applied to insects having only one pair of wings (anterior): thorax agglutinate; mouth haustellate; transformations complete.

Dipterocecidium: a gall formed by a dipterous insect.

Dipterous: belonging to or having the characters of Diptera.

Direct: applied to metamorphosis = incomplete.

Directive coloration: directive marks or colors which tend to divert the attention of an enemy from more vital parts.

Disc: see disk.

Discal: on or relating to the disc of any surface or structure.

Discal area: of a wing applies especially to the more central portion, or that area covered by the discal cell.

Discal bristles: Diptera; are inserted on the middle of the abdominal segments before the hind margin.

Discal cell: Lepidoptera; the large or median cell extending from the base of the wing toward the center: = radial cell (Comst.): in Diptera (Will.) = 1st medial 2 (Comst.): Odonata; = discoidal areolets, q.v.: Trichoptera, the cell between the forks of the radial sector, and separated from the 2d apical cell by a cross-vein.

Discal patch: in some male Hesperidae the oblique streak of specialized black scales on the disc of the primaries.

Discal vein: Lepidoptera; the cross-vein closing the discal or median cell extends from radius 5 to media 1.

Disciform: formed or shaped like a disc.

Discocellular nervure or vein: Lepidoptera; = discal vein, q.v.

Discoidal: relating to the disc, or middle = discal.

Discoidal area: the middle area or field: Trichoptera; that area of the tegmina between the posterior or a.n.a.l and the anterior or costal areas = d. field.

Discoidal areolets: Odonata; a varying number of rows of cells on the outer side of the triangle between the short sector (M 4 of Comst.) and the upper sector of the triangle (Cu 1 of Comst.) = post-triangular cells := discal cells.