Definitions For Glossary Terms

OBLIQUE
Slanting in any direction between vertical and horizontal.
OBLONG
Somewhat longer than broad (compare with elongate).
OBSOLESCENT
Very faintly indicated, almost gone.
OBSOLETE
Absent.
OCCIPITAL CARINA
An upside-down U-shaped ridge on the back or posterior surface of the head; the occipital carina differentiates the posterior occiput and postgenae from the dorsal vertex and temples and lateral genae (see also genal carina). [drawing][photo]
OCCIPITAL FORAMEN
Opening on the posterior surface of the head through which organs of the head and body are connected; sometimes called the foramen magnum. [drawing][photo]
OCCIPITAL MARGIN
Abruptly angled or carinate posterodorsal margin of the head that differentiates a dorsal surface from an abruptly declined posterior surface (see also occipital carina).
OCCIPITAL SUTURE
In Mymaridae, term used for a groove on the sides and back of the head in a position similar to the occipital carina of many other chalcids, but which extends from the malar sulcus and likely is synonymous with the postgenal sulcus. [photo]
OCCIPUT
Posterior surface of the head above the occipital foramen. [drawing][photo]
OCELLAR AREA
See stemmaticum
OCELLAR TRIANGLE
Region of the head delimited by the three ocelli.
OCELLAR-OCULAR GROOVE
Term used for a transverse groove between the posterior ocellus and upper margin of the eye in some Eucharitidae (see also vertexal sulcus).
OCELLOCULAR LINE
Minimum distance between a posterior ocellus and eye margin, abbreviated as OOL or OOD. [drawing]
OCELLUS
(pl., ocelli) One of typically three bead-like lenses usually arranged in a triangle near the dorsal surface of the head; sometimes referred to as a simple eye in contrast to the compound eye. [drawing]
OLISTHETER
Term used for the composite tongue-and-groove interlocking mechanism of the first valvulae and second valvulae of the ovipositor stylets, and consisting of the aulax and rhachis, respectively. [drawing]
OMMATIDIUM
(pl., ommatidia) Single sensory cell of a compound eye (see also facet). [drawing][photo]
OOD
See ocellocular line
OOL
See ocellocular line
OPEN LINEA CALVA
A linea calva in which the bare band is continuous to the posterior margin of the wing, not being entirely or substantially closed posteriorly by setae; by definition an open linea calva can be an entire linea calva or an interrupted linea calva, but not a closed linea calva.
ORAL CAVITY/FOSSA
See mouth cavity
ORBIT
See eye margin
ORTHOGNATHOUS
Position of the head if the long axis is oriented more or less vertically and the mouthparts are directed ventrally; sometimes used as synonym of hypognathous.
OUTER PANEL OF AXILLA
See lateral panel of axilla
OUTER PLATE OF OVIPOSITOR
Anterior, lateral part of the U-shaped last metasomal tergum, which articulates anteriorly with the first valvifer of the ovipositor (see also inner plate of ovipositor and ovipositor sheaths). [drawing][drawing][drawing]
OVAL/OVATE/OVOID
Sometimes used for a symmetrical elliptical shape, but more correctly designating an egg shape, i.e. with one narrower and one broader, rounded end (see also lanceolate and spatulate).
OVIPOSITOR
Composite term for the egg-laying apparatus of females, which consists of the outer ovipositor sheaths and inner drilling ovipositor stylets, but sometimes used only for the stylets. [drawing][drawing]
OVIPOSITOR SHEATHS
Paired outer protective sclerites surrounding the ovipositor stylets, which are formed from the third valvulae or gonostyli; the term is sometimes used to include the inner plate of the ovipositor but more correctly is the slender apical portion that often is differentiated from the inner plate by a slight constriction (see also outer plate of the ovipositor). [drawing][photo][drawing]
OVIPOSITOR STYLETS
Inner, drilling structures of the ovipositor; the term is sometimes used only for the actual cutting valves, the second valvulae, and sometimes for the combined second valvulae and interlocked stylet sheath or first valvulae. [drawing][drawing]