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, sexual or geographic. Dioecious: with distinct sexes. 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 labial 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 anal 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. 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.