Hymenoptera Glossary and Ontology Initiative
The glossary linked here
is a product of an ongoing effort by the community to build an ontology of morphological terms used by hymenopterists.
The ontology is fully accessible and editable through the web, and interested parties are encouraged to get involved in its development.
Hymenoptera of the World: A glossary of terms from the keys
Unless otherwise noted the glossary below and its illustrations are
from the text:
Huber J.T & M.J. Sharkey. 1993. Structure, pp. 13-59. In Goulet, H. &
J.T. Huber eds. Hymenoptera of the world: An identification guide to Families.
Centre for Land and
Biological Resources Research, Ottawa, Ontario. 668pp.
| U - Z
- abdomen (adj.
The principal posterior division of the body, posterior to the leg-bearing
segments and composed of 10 or fewer apparent segments; in most Symphyta
abdominal segment 1 is easily recognized by its median split (cf. metasoma,
- abscissa (pl.,
A segment of a wing vein that is delimited by the intersection of other
Sharply angled, less than 90 degrees.
(pl., antennae; adj., antennal)
A paired, segmented sensory appendage of the head between the compound eyes,
which consists of three segments having intrinsic muscles (see also scape,
pedicel, and flagellum).
Toward or at the front end of the body or structure (front, frontal).
- apex (pl., apices; adj., apical, apico-)
Part of a structure farthest from its point of attachment to the body.
The end farthest away from the body; at or toward the tip (see also distal).
- areola (pl.,
areolae; adj., areolate)
In Ichneumonidae, the median area of the propodeum that is enclosed by ridges
in Braconidae this is the median areola.
In Ichneumonidae, the small cell in the centre of the fore wing; the second
- arolium (pl.,
A pad-like median lobe between the tarsal claws (see also pretarsus).
- axilla (pl.,
axillae; adj., axillar)
In groups with a transscutal articulation, posterolateral portion of the
mesoscutum separated from the mesoscutum lateral to the scutellum; usually
triangular (see also scutum).
- axillula (pl.,
axillulae; adj., axillular)
In Chalcidoidea, the lateral subdivision of the scutellum delimited by a
The end closest to the body (base); at or toward the base (proximal).
- base (adj., basal, base-)
The end closest to the body (base); at or toward the base (proximal).
In Apoidea, a small, flat, hairless, raised region of the dorsal surface
of the metatibia at its base.
- bulla (pl.,
Unpigmented area of a vein where it is crossed by a wings fold or line of
- cardo (pl.,
The basal part of the maxilla.
- carina (pl., carinae; adj., carinate)
A ridge or raised line.
The area between the veins of a wings; it is closed when completely surrounded
by veins, otherwise it is open (see morphology section for naming cells).
- cenchrus (pl.,
In Symphyta, a paired, circular, or oval structure on the sublateral portion
of the metascutum that is used to hold the wings in place when not being
- cercus (pl.,
cerci; adj., cercal)
A paired, posterior, sensory appendage of the last (morphological tenth)
abdominal tergum, which usually bears setae. With a reduction of the apical
segments of the metasoma, the cerci often appear to be on a more anterior
- claval lobe (pl., chelae; adj., chelate)
The posterior portion of a wing behind the claval fold and in front of the
jugal fold, when present (see also jugal lobe).
The furrow on the fore wing just anterior to, and parallel with, vein 1A
(first anal), and extending to the claval notch on the wing margin.
Enlarged apical flagellomere or flagellomeres of an antenna (see also funicle).
- clypeus (adj.,
The medial sclerite of the head immediately above the labrum; often defined
dorsally and laterally by the epistomal groove.
Flattened from side to side (higher than wide).
Pertaining to a linear structure, margin, or surface that is curved inward
- corbicula (pl.,
In bees, the concave, smooth region of the metatibia that is marginated
by a fringe of setae arising from the margins; it forms a pollen basket.
The excision of the wing margin between the apex of the costal vein and
the base of the stigma.
The first segment of a leg, between the body and the trochanter.
Flattened from top to bottom (wider than high).
- disc (adj., discal)
The central surface of any structure.
Toward or at the top or upper surface of the body or structure (below).
Notched; with a obtuse, rounded, or quadrate section cut out of a margin.
A mandible with the teeth facing inward so that when the mandibles are closed
their tips point toward each other's base (cf. exodont).
The ridge on the mesopleuron located directly posterior to the fore coxae
that more or less parallels the anterior margin of the mesepisternum and
that delineates the posterior margin of the epicemium.
- epicnemium (adj.,
The anterior portion of the mesopleuron delimited posteriorly by the epicnemial
carina (see also prepectus).
- epimeron (pl.,
epimera; adj., epimeral)
The portion of a pleuron posterior to the pleural groove (cf. episternum).
In Chalcidoidea, a small, more or less sclerotized, fingernail-like flap
attached to the last metasomal tergum between the cerci.
- episternal groove
See mesepisternal groove.
- episternum (pl.,
eisterna; adj., episternal)
The portion of a pleuron anterior to the pleural groove (cf. epimeron).
A groove defining the lateral and dorsal margin of the clypeus.
- epomia (pl.,
In Ichneumonoidea, an oblique ridge crossing the transverse furrow on the
side of the pronotum.
mandible (pl., epomiae)
A mandible with the teeth facing outward so that when the mandibles are
closed their tips point anteriorly or away from each other (cf. endodont).
- face (adj.,
In Parasitica, the anterior surface of the head between the eyes from the
ventral margin of the toruli to the oral cavity, excluding the clypeus;
in Symphyta and Aculeata, the anterior surface of the head between the eyes
from the ocelli to the oral cavity, including the clypeus.
In Apoidea (bees), a depressed, often finely and densely pubescent area
along the inner orbit of a compound eye.
In Multillidae and Brandynobaenidae, a longitudinal line of flattened setae
and secretory pores laterally on metasomal tergum 2.
- femur (pl.,
femora; adj., femoral)
The third segment of a leg, between the trochanter and tibia (c.f.trochantellus).
- flabellum (pl.,
In Apoidea (bees), a small thin plate at the apex of the glossa.
A segment-like subdivision of the flagellum; they are numbered consecutively
from the base of the flagellum.
- flagellum (pl.,
flagella; adj., flagellar)
The third primary division or segment of the antenna; it articulates with
the pedicel basally and almost always is subdivided into flagellomeres.
- foramen (pl.,
A hole in the body wall through which vessels or nerves pass. The foramen
magnum is the central hole in the back of the head; the propodeal foramen
is the holde in the posterior area of the propodeum.
- frenum (pl.,
frena; adj., frenal)
In Chalcidoidea, the transverse line on the scutellum that delineates a
posterior portion of the scutellum, the frenal area.
The area of the head between the ventral margin of the toruli and the anterior
margin of the median ocellus. (note: this is equivalent to the true frons
of the larvae).
A longitudinal ridge or pair of ridges on the frons between (and sometimes
partly covering) the toruli.
- funicle (adj.,
A group of flagellomeres between the pedicel and the club.
- galea (pl.,
The outer apical lobe of the maxilla, articulated basally with the stipes.
- gastrocoelus-thyridium (pl.,
In Ichneumonidae, the usually transverse impression anterolaterally on metasomal
tergum 2. The gastrocoelus includes the thyridium (t) which is the surface
area with specialized sculpture, whereas the gastrocoelus is the impression
- gena (pl.,
genae; adj., genal)
The cheek; the lateral part of the head between the compound eye and, when
present, the occipital carina; otherwise, the lower (in hypognathous head)
or anterior (in prognathous head) part of the back of the head between the
compound eye and the occiput.
- glossa (pl.,
The paired, fused, median lobe of the labium articulated basally with the
- glymma (pl.,
In Ichneumonidae, the groove or pit on either side of metasomal segment
1 between its base and the spiracle; it is nearly always present when sternum
1 is free from tergum 1 but absent when tergum 1 and sternum 1 are fused.
A linear impression on a sclerite (see also suture).
- hamulus (pl.,
One of a series of small bristle-like hooks on the anterior margin of the
hind wing; in some groups there may be a basal and an apical series of hamuli.
The principal anterior division of the body; it bears the mouthparts and
The anterior sclerite of the wing at the base of vein C (costa).
With the head more or less at a right angle to the plane of the body (vertical),
so the mouthparts are directed ventrally (cf. prognathous).
- hypopygium (adj.,
The last visible sternum of the abdomen.
The sclerotized posterior part of the head that sometimes separates the
foramen magnum from the oral cavity that normally delimits the hypostoma
from the postgena and occiput.
The posterior area of the wing behind vein 1A (first anal) and set off from
more anterior areas by a slight fold (jugal fold) on the wing and by a notch
on the wing margin (see also claval lobe).
- labium (adj.,
The posterior, medial appendage of the mouthparts between and behind the
maxillae, composed of the submentum, mentum, prementum, glossa, paraglossa,
and labial palpi.
- labrum (adj.,
The anterior, medial appendage of the mouthparts attached to the underside
of, and often concealed by, the clypeus.
- lacinia (pl.,
The inner apical lobe of the maxilla, articulated to the stipes.
- lamina (pl., laminae; adj., laminate)
A thin plate or leaf-like process.
Toward or at the side of the body, or the side margin or edge of a structure.
The lateral part of an abdominal/metasomal tergum that is marked by a crease
or groove, or is even completely detached from the main dorsal part of the
tergum (see also tergite, tergum).
The shortest distance between the base of the mandible and the margin of
the compound eye.
- mandible (adj.,
The paired, heavily sclerotized biting and chewing lateral appendage of
the mouthparts between the labrum and maxilla.
- maxilla (pl.,
maxillae; adj., maxillary)
The paired appendage of the mouthparts between the mandible and the labium,
consisting of the cardo, stipes, lacinia, galea, and maxillary palpus.
Toward or at the center, or central area or line, of the body or structure
A labial sclerite articulating basally with the submentum and apically with
the prementum; often fused with the latter and indistinguishable as separate
The posterior subdivision of the mesopleuron, usually small (sometimes almost
absent) relative to the mesepisternum.
A groove on the mesopleuron, extending ventrally from a pit under the base
of the forewings and, when complete, reaching the anteroventral margin of
The anterior subdivision of the mesopleuron, usually comprising most of
A Greek prefix meaning middle or mid; used with Latin, latinized, or Greek
words to indicate the middle (often second) part of a structure.
The dorsal part of the mesothorax.
The lateral and ventral part of the mesothorax (see also mesosternum).
- mesoscutal lobe
In Symphyta, the posterior subdivision of the mesoscutellum, usually crescent-shaped
and overhanging the postnotum of the mesothorax.
The mesonotum excluding the scutellum; in groups with a transscutal articulation,
the portion of the mesonotum anterior to the articulation; the mesoscutum
is usually divided by the notauli into a medial part and two lateral lobes
(see also scutum).
- mesosoma (pl.,
mesosomata; adj., mesosomal)
adj., mesosomal) In Apocrita, the thorax plus the propodeum (cf. thorax).
The sternum of the mesothorax, usually invaginated and not visible; sometimes
inappropriately used as a general term for the ventral surface of the mesothorax,
such as when it is modified into a flat plate with posteriorly projecting
lobes (see .also mesopleuron).
The second and largest of the three primary subdivisions of the thorax,
bearing the middle pair of legs and, when present, the forewings.
The ventral part of the mesothorax inflected towards the metasternum beneath
the base of the mesocoxae; visible only by removing the mesocoxae.
A Greek prefix meaning hind or posterior; used with Latin, latinized, or
Green words to indicate the posterior (usually third) part of a structure).
The dorsal part of the metathorax.
The lateral and ventral part of the metathorax.
- metasoma (pl.,
metasomata; adj., metasomal)
In Apocrita, the apparent abdomen, consisting of the abdomen, excluding
the first segment or propodeum which is fused withe the thorax to the mesosoma
The sternum of the metathorax, usually invaginated and not visible but sometimes
used as a general term for the ventral surface of the metathorax.
The third of the three primary subdivisions of the thorax, bearing the hind
pair of legs and, when present, the hind wings.
The posterior subdivision of the metapleuron.
The anterior subdivision of the metapleuron.
The appendages of the head used for feeding, including the labrum, hypopharynx,
mandibles, maxillae, and labium.
- nebulous vein
A wing vein that is uniformly pigmented (not darker on its margins), without
a tubular structure; it can be seen with both reflected and transmitted
light (cf. spectral tubular veins).
- notaulus (pl.,
The usually oblique longitudinal groove on the mesoscutum, often dividing
the mesoscutum into medial and lateral parts.
- notopleural suture
A groove separating the mesonotum from mesopleuron.
- notum (pl., nota; adj., notal)
A thoracic tergum, usually subdivided into a scutum and a scutellum.
- notum (pl., nota; adj., notal)
A thoracic tergum, usually subdivided into a scutum and a scutellum.
- oblique scutal carina
In sphecidae s.l., the ridge on the mesoscutum extending obliquely posteriorly
and medially from the lateral margin near the posterior of the tegula.
A ridge on the posterior surface of the head that separates the occiput
from the vertex and gena; the ventral part of the ridge is sometimes called
the genal carina.
- occiput (adj.,
The posterior part of the head behind the vertex dorsally and the genae
laterally. If the an occipital carina is present, the occiput is the area
between it and the very narrow postocciput surrounding the foramen magnum
(see also postgena).
- ocellus (pl.,
oceli; adj., ocellar)
A simple eye, consisting of a single, usually round or oval facet. Hymenoptera
usually have three ocelli: one median (anterior) and two lateral (posterior).
- oral cavity
The opening of the head from which the mouthparts are suspended.
The narrow border around the eye. The inner and outer orbits are those parts
of the face plus the frons and the gena, respectively, immediately next
to the eye.
In females, a slender, paired and interlocking, saw-like or tubular structure
used for laying the eggs or, in Aculeata, for stinging or, in some Ichneumonoidea,
for both; it may be concealed or may extend beyond the apex of the body
and is protected by a pair .of ovipositor sheaths.
A paired, sclerotized structure enclosing the external part of the ovipositor.
- palpus (pl.,
palpi; adj., palpal)
Pared sensory appendages of the maxilla and labium, consisting of one to
six segments and one to four segments, respectively.
- paraglossa (pl.,
A paired, lateral lobe of the labium articulated basally with the prementum
lateral to the base of the glossa.
The second primary division or segment of the antenna; it articulates apically
with the flagellum and basally with the scape.
An intermediate, club-like condition between sessile and petiolate (see
Part of the metasome, usually metasomal segment 1; the usually narrow, parallel-sided
stalk joining the rest of the metasoma to the propodeum.
sensillum (pl., sensilla)
An elongate, appressed, plate-like or rounded roof-like or groove-like sensory
structure; it is usually mentioned when referring to the flagellomeres.
A small membranous pad projecting from the ventral apex of tarsomeres 1-4.
A groove on the mesopleuron and metapleuron extending between the wing base
and the coxal articulation; it separates the episternum from the epimeron.
- pleuron (pl.,
pleura; adj., pleural)
The lateral part of a body segment, commonly of a thoracic segment where
the pleuron occupies the lateral as well as the ventral areas of the mesothorax
Toward or at the hind end of the body or structure (rear, back).
A sclerite on the posterior (ventral) surface of the glossa.
- postgena (adj.,
The lower part of the occiput; when the occipital carina is absent, the
gena and postgena are continuous, and the entire lower area constitutes
the gena (see also occiput).
A posterior sclerite of the mesonotum and metanotum behind the scutellum.
The postnotum of the metathorax is fused dorsally with abdominal tergum
1 and laterally with the metepimeron; in apocrita the postnotum is rarely
visible, and then only as an .impressed line in front of the propodeum.
- postocciput (adj.,
A narrow area surrounding the foramen magnum; it is separated from the occiput
by the postoccipital groove.
In Ichneumonoidea, the posterior transverse carina ventrally on the mesopleuron,
just in front of the mesocoxa.
A labial sclerite articulating basally with the mentum and bearing the glossae,
paraglossae, and palpi apically.
A sclerite of the thorax between the pronotum and the mesepisternum (see
The enlarged and sclerotized apex of one or more veins on the anterior margin
of the wing basal to the costal notch and almost continuous with the stigma.
The apical segment of a leg, bearing the claws and associated structures
(see also arolium).
A Latin prefix meaning before or anterior; used with Latin, latinized, or
Greek words to indicate the anterior (usually first) part of a structure.
With the head more or less in the same plane as the body (horizontal) so
the mouthparts are directed anteriorly (cf. hypognathous).
The horizontal surface of the pronotum posterior to the sloping, and often
narrowing, region immediately behind the head.
The anterior projecting rim of the pronotum; it is often hidden by the head.
The rounded posterolateral extension of the pronotum covering the mesothoracic
In Cynipoidea, the dorsal disc of the pronotum.
- pronotum (adj.,
The dorsal sclerite of the prothorax; in most Hymenoptera, occupying also
the dorsolateral or lateral part of the prothorax.
- propleuron (pl.,
The lateral part of the prothorax. In hymenoptera, it is displaced somewhat
by the pronotum so as to occupy an oblique position ventrolateral and anterior
to the pronotum.
In Ichneumonoidea, one or more named, usually distinct, transverse or longitudinal
ridges on the propodeum.
- propodeum (adj.,
In Apocrita, the first tergum of the abdomen, widely and immovably fused
with the metanotum and with each metapleuron of the thorax, and usually
narrowly and flexibly joined to the rest of the abdomen (see also abdomen,
A ventral sclerite of the prothorax, between the propleura.
The first of the three primary subdivisions of the thorax, composed of the
pronotum, the propleuron, and the prosternum.
The short, fine, often closely set setae on the body.
Bearing fine, impressed points or pits.
A specialized area of the tergum of the last externally visible segment of the metasoma; it is usually flattened and defined laterally by ridges or grooves.
The basal part of the scape often strongly defined by a constriction; it
articulates with the torulus.
Referring to a seta lying parallel to the body surface.
Covered with a network of lines; meshed.
The first primary division or segment of the antenna; it articulates apically
with the pedicel and basally with the torulus.
A hardened plate of the integument; it is separated from other such plates
by sutures or membrane.
Referring to the body integument; relatively stiff and usually darkly pigmented
areas compared with usually colorless and flexible membranous areas.
- scopa (pl., scopae)
In Apiformes, a brush-like structure of short stiff hairs of equal length
used for collecting pollen.
A horizontal groove on the mesopleuron that may be continuous with the episternal
groove anteriorly and ends at the pleural grove posteriorly.
- scrobe (adj.,
A groove in the body integument for the reception or concealment of an appendage,
e.g., A longitudinal depression of the head above each torulus for reception
of the scape or a groove on the mesopleuron for reception of the mesofemur;
the .scrobe of the mesepisternum is a small pit.
Markings or a pattern of impressions or elevations on the surface of a structure.
- scutellum (pl.,
scutella; adj., scutellae)
The middle region of the mesonotum or metanotum, behind the scutum. In apocrita,
only the mesoscutellum is evident and is simply called the scutellum, whereas
in symphyta both the mesoscutellum and metascutellum are present.
- scutum (pl.,
scuta; adj., scutal)
The anterior sclerite of a notum, in front of the scutellum. In apocrita,
the mesoscutum is functionally only the area in front of the transscutal
articulation; the axilla, although morphologically part of the mesoscutum,
is treated as separate (see also axilla).
A ring or subdivision of the body or of an appendage between areas of flexibility,
and bearing intrinsic muscles.
- sensillum (pl., sensilla)
A simple sense organ, such as a seta, or one of the structural units of
a compound sense organ.
One structure attached to another, without a distinct constriction (cf.
- seta (pl., setae; adj., setal)
A slender, hair-like, usually sensory extension of the cuticle, connected
to the body wall by a socket.
- spectral vein
A wing vein that is indicated only by a ridge or furrow on the wing surface;
it has no trace of pigment and can only be seen with reflected light (cf.
tubular, nebulous veins).
- spiracle (adj.,
A small, round or oval lateral opening on a body segment through which air
enters the tracheae.
- sternaulus (pl.,
The horizontal lateroventral carina or groove near the lower margin of the
mesopleuron, extending from the lower end of the epicnemial carina toward
The sclerotized subdivision of a sternum bounded by grooves or by membranous
lines or areas (see also sternum).
- sternum (pl.,
sterna; adj., sternal)
The ventral division of a body segment, which may be subdivided into sternites;
usually only refers to the segments of the abdomen/metasoma and to the prothorax.
The sterna of the mesothorax and metathorax are considered to be invaginated
within the thorax.
A thickly sclerotized and usually darkly pigmented area on the fore wing
margin at the apex of the costal vein. In Chalcidoidea, a knob-like enlargement
of the apex of the stigmal vein.
- stipes (pl.,
stipites; adj., stipital)
A major sclerite of the maxilla, articulating basally with the cardo, apically
with the galea and lacinia, and laterally with the maxillary palpus.
Latin prefix meaning under; also used commonly to mean somewhat or almost
(e.g., subequal is synonymous with almost equal).
In Apiformes, one or two fine grooves between the torulus and the clypeus.
A ridge bordering the gena ventrally; it extends from the hypostomal carina
to the anterior or facial articulation of the mandible.
The basal sclerite of the labium articulating apically with the mentum;
in Apoidea, an often V-shaped sclerite (often called the lorum) with an
arm articulating with each cardo and medially articulating with the mentum.
A ridge on the ventral margin of the lower part of the metapleuron, between
the bases of the mesocoxae and metacoxae.
A groove extending from the ventral margin of the eye to the anterior or
facial articulation of the mandible.
A line or membranous area on the cuticle indicating the junction of two formerly separate plates or sclerites (see also groove).
A subdivision of the tarsus; each tarsus has 3 - 5 tarsomeres.
- tarsus (pl.,
tarsi; adj., tarsal)
The fifth segment of a leg, attached basally to the tibia and subdivided
- tegula (pl.,
A small, scale-like sclerite covering the base of the fore wing, basal to
the humeral plate.
A sclerotized subdivision of a tergum bounded by grooves, or membranous
lines or areas (see also laterotergite, tergum).
- tergum (pl.,
terga; adj., tergal)
A dorsal sclerite of a body segment, which may be subdivided into tergites;
specifically used for the abdomen/metasoma (see also laterotergite).
- thorax (pl.,
thoraces; adj., thoracic)
The principal middle division of the body to which the legs are attached,
between the head and abdomen (cf. mesosoma).
- tibia (pl.,
tibiae; adj., tibial)
The fourth segment of a leg, between the femur and the tarsus.
A spine-like, multicellular extension of the cuticle connected to an appendage
by a socket; usually found on the tibiae.
- torulus (pl.,
A paired socket or. the front of the head upon which the scape is articulated.
A line of weakness across the mesonotum between the fore wing bases, which
secondarily separates the posterolateral angles of the mesoscutum beside
the scutellum (see also axilla, scutum).
The basal end of the femur; it looks like a second segment of the trochanter.
The second segment of a leg, between the coxa and femur.
Cut off squarely at the tip. tubular vein A pigmented wing vein that is hollow and therefore appears darker laterally and lighter medially; it can be seen with both reflected and transmitted light (cf. nebulous,spectral veins).
- vein (adj.,
Narrow, usually dark thickenings of a wing arising at the wing base and
branching towards the apex (see also nebulous, spectral, tubular veins,
and morphology section for naming of veins).
The top of the head between the eyes, from the anterior margin of the median
ocellus to the occiput.
- volsella (pl., volsellae)
A paired, median inner appendage of the male genitalia.