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TERMINOLOGY IN INSECT MORPHOLOGY

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ABDOMEN - The posterior of the three principal divisions or tagmata of the insect body composed of no more than 12 metameres; functionally, the abdomen is the seat of reproduction and contains the visceral systems of digestion, elimination, respiration, circulation, storage and reproduction.

ABDUCTOR - Referable to a structure or tissue, which draws away, or outward from the central body of an animal or a structure.

ABDUCTOR MUSCLE - A muscle that pulls a structure away from the central body of an animal or a structure.

ABDUCTOR TENDON - An apodeme to which the abductor muscle is attached; a broad, flat apodeme attached to the ectal margin of the mandible.

ADDUCTOR - Referable to a structure or tissue, which draws into or toward the central body of an animal, or a structure.

ADDUCTOR MUSCLE - A muscle that pulls a structure toward the central body of an animal or a structure.

ADDUCTOR TENDON - An apodeme to which the adductor muscle is attached; a broad, flat apodeme attached to the ental margin of the mandible.

ADFRONTAL AREA - A sclerite located between the epistomal suture and the adfrontal suture on the facial region of lepidopterous larvae; a possible remnant of the frons.

SUTURE - A suture or faintly defined line that parallels the epistomal suture in lepidopterous larvae.

ALVEOLUS (Pl. ALVEOLI) - A pocket in the cuticula accommodating a seta or similar unicellular structure.

AMBULATORY APPENDAGE - Any tubular evagination of the body wall used for walking; a leg.

ANATOMY - A detailed study or description of structure, or a reference to structure.

ANNULATIONS - A series of minute parallel ridges partially or completely ringing a structure such as the glossa of Apis mellifera or the galea of Heliothis zea.

ANTECLYPEUS - A distal membranous portion of the clypeus.

ANTENNA (pl. ANTENNAE) - A segmented, sensory appendage of variable length and design located on the frontal or lateral margins of the head.

ANTENNAL SCLERITE - A peritreme or ring-like sclerite at the base of the antenna.

ANTENNAL SUTURE - A suture separating the antennal sclerite from the sclerites of the head.

ANTERIOR ARTICULATTON - Referring to the depression or knob on the mandible or subgena upon which the anterior angle of the mandible articulates with the head capsule.

ANTERIOR TENTORIAL ARMS - The anterior invaginations or apodemes which make up the tentorium; the legs of a TT-shaped or A-shaped tentorium.

ANTERIOR TENTORIAL PITS - The pits or depressions of the body wall marking the points of invagination of the anterior tentorial arms.

ANUS - The exterior and posterior opening of the hind gut.

APPENDAGES - Any of the evaginations of the body wall whicharticulate with the body wall and serve a sensory, locomotory, or reproductive function; legs, wings, antennae, cerci, etc.

APODEME - A multicellular invagination of the body wall; structures comprising the endoskeleton.

ATRIUM - Any chamber or cavity at the entrance or a body opening; in Musca domestica larva, the preoral cavity.

AXON - A process or nerve fiber of a nerve cell or neuron.

BASEMENT MEMBRANE - The fibrous non-cellular sheath underlying the epidermis of the integument.

BODY WALL - The integument; all of the elements of the integument including the cuticula, epidermis and basement membrane.

BUCCULA - In Oncopeltus fasciatus, a descriptive term for the vertical plates of the head arising ventrally on either side of the base of the labium.

CANALICULUS (pl. CANALICULI) - Any minute canal; the tubes traversing the ectal surface of the labella in the larva of Musca domestica.

CANTHUS - In Phyllophaga rugosa, a descriptive term for the sclerlte invading the compound eye at the lateral margins of the clypeus.

CARDO - The proximal sclerite of the maxilla articulating with the postgena and the stipes.

CEPHALIZATION - An evolutionary trend toward the coalescence especially of sensory structures anteriorly or within the head capsule.

CEPHALOPHARYNGIAL SKELETON - A descriptive term for the sclerotized portions of the rasping and sucking mechanism in muscoid larvae; collectively, the mouth hook, hypostomal sclerite and cibarium.

CERCUS (pl. CERCI) - A pair of posterior sensory appendages arising from the tenth metamere; usually segmented, long and filamentous.

CERVICAL PLATE - In the larva of Phyllophaga rugosa, a sclerotization of the cervix forming a broad plate which is adnate with the posterior aspect of the head and attached to a narrow postocciput.

CERVIX - The neck or membranous sheath connecting the head and thorax.

CHAETOTAXY - The descriptive anatomy of setal patterns particularly on the head, thorax and abdomen of larvae, but also including such areas as the ental surface of the labium.

CHALAZA - A multicellular protrusion or evagination of the body wall; usually a descriptive term referable to protrusions bearing a large seta.

CHEMORECEPTOR - A specialized structure, usually a seta, provided with sensory nerves for the reception of chemical stimuli.

CHITIN - One of the basic constituents of the exocuticle and endocuticle of the cuticula; a polysaccharide chemically identified as a poly acetylglucosamine.

CIBARIAL DILATOR MUSCLES - Muscles arising from the clypeus which dilate the cibarium, or specifically operate the cibarial diaphragm.

CIBARLAL PUMP - A modification of the cibarial cavity into a pumping device; contraction of the cibarial dilator muscles expand the membranous walls of the cibarial cavity or raise a cibarial diaphragm; contraction of the cavity or diaphragm is accomplished by a return to its normal (unexpanded) shape by means of the natural elasticity of its cuticular composition.

CIBARIUM - The cavity preceding the mouth formed by the ental surface of the clypeus and the dorsal surface of the hypopharynx.

CLYPEUS - A facial sclerite lying between the epistomal suture and the juncture of the labrum with the head capsule; usually the region lying below the epistomal suture or anterior tentorial pits.

COLLECTING CHANNEL - In the adult of Musca domestica, a descriptive term for the canaliculi paralleling the discal sclerite into which the canaliculi of the labella empty or terminate.

COMMISSURE - A connective between two bilaterally symmetrical tissues or structures; e.g., the connective between two hemispheres of a ganglion or two longitudinal trunks of the respiratory system.

COMPOUND EYE - A photoreceptor comprised of numerous but separate visual elements each of which is provided with an individual lens or dioptric apparatus.

CONDYLE - An articulatory structure as a ball-shaped protuberance which is usually accommodated by a groove or socket to form a joint.

CONJUNCTIVAL MEMBRANE - The membranous invagination or infolding of the body wall between metameres or between tergites and sternites; actually this is a suture, although the term is reserved for sutures which permit articulation and expansion between large sclerotic areas.

CORONAL SUTURE - The stem of the Y-shaped epicranial or ecdysial suture of the head.

COXA (pl. COXAE) - The basal or proximal segment of the leg which articulates directly with the body wall.

COXAPODITE - The basal elements of a primitive leg; composed of a subcoxa (or pleurites) and a coxa.

COXITE - Divisions of a coxapodite such as the subcoxa and coxa.

CUTICULA - That portion of the body wall which is secreted by the epidermis and is cast off during ecdysis; collectively the epicuticle, exocuticleand endocuticle. 

DEUTOCEREBRUM - The median lobe of the supraoesophagial ganglion; the ganglion which innervates the antennae.

DICHOPTIC - A descriptive term for Musca domestica relative to the distance of separation between the compound eyes; in female Musca domestica as compared with the male the eyes are widely separated.

DICONDYLIC ARTICULATION - A dual hinge or two specific points at which a structure is articulated.

DIOPTRIC APPARATUS - The light receiving element or lens of a photoreceptor or eye; usually includes the cornea and subcorneal crystalline body.

DISCAL SCLERITE - In the mouth parts of adult Musca domestica, a descriptive term for a V-shaped sclerite margining the prestomum of the labella.

DISTAL - Any point or segment furthest removed from the body mass or structure bearing it.

DISTAL PLATE OF THE PREMENTUM - In Apis mellifera, a descriptive term for the narrow plate anterior to the prementum.

DORSAL GUTTER - A dorsal, longitudinal groove in the proboscis or labium of Oncopeltus fasciatus; a channel which ensheathes the stylets.

DORSAL LATERAL PLATE - One of the principal articulatory sclerites of the cervix; part of a hinge sclerite.

DORSAL SENSORY PAPILLAE - In the larva of Musca domestica, a dorsal pair of minute, sensory projections at the anterior aspect of the larval head.

ECDYSIAL SUTURE - A Y-shaped cranial suture found in larvae and some adults along which the integument is ruptured during molting; the epicranial suture.

ECTAL - Any surface furthest removed from the principal body mass.

ENDITE - A mesal lobe of the coxapodite.

ENDOCUTICLE - The innermost layer of the cuticula lying between the exocuticle and the epidermis.

ENDOSKELETON - Collectively, the multicellular invaginations of the integument or apodemes, e.g., tentorium

ENTAL - Any surface nearest the principal body mass.

EPICRANIAL SUTURE - A Y-shaped cranial suture occurring in larvae and some adults; the ecdysial suture of larvae.

EPICUTICLE - The thin, outermost layer of the cuticula.

EPIDERMIS - The epithelial layer of cells which secrete the cuticula; the hypodermis of authors.

EPIPHARYNX - A membranous lobe in the oral cavity of Apis mellifera arising from the ental surface of the clypeus; a flap underlying the labrum (but not a part of it).

EPISTOMAL RIDGE - The infolding or apodeme of the epistomal suture to which the anterior arms of the tentorium are anchored; usually a prominent endoskeletal projection.

EPISTOMAL SUTURE - A transverse cranial suture bearing the anterior tentorial pits and demarcating the clypeus and the frons.

EVAGINATION - An outward projection or protrusion of the body wall.

EXITE - A lobe of the coxapodite occurring on the outer or ectal surface of the appendage.

EXOCUTICLE - The middle, sclerotized layer of the cuticula.

EXOSKELETON - Refers to the sclerotized integument which serves mechanically as a skeleton.

EYES - Any of the photo receptors such as the compound eyes and ocelli.

FEMUR - The second proximal segment of the telopodite; the leg segment articulating with the trochanter and the tibia.

FOOD CANAL - Any of the tubes formed by grooved and closely appressed structures used for conducting liquid foods in haustellate mouth parts.

FOOD CHANNEL - In the larva of Musca domestica, the series of parallel grooves on the ventral surface of the larval head which appear to aid in channeling fluids into the functional mouth; in the haustellate mouth parts, the tube through which liquids are drawn.

FOOD GLANDS - Extensively coiled, lobular glands with ducts on the posterior lateral margins of the hypopharyngial lobe in the worker caste of Apis mellifera; these glands secrete the royal jelly fed to bee larvae; the hypopharyngial glands.

FOSSA OF THE PROBOSCIS - In Apis mellifera, the ventral depression of the head which accommodates the labium or basal portion of the proboscis.

FRONS - A facial area of the head dorsad of the epistomal suture and between the compound eyes; the facial area enclosed by the frontal sutures of the epicranial or ecdysial suture; the "front" of authors.

FRONTAL BRACE - In the larva of Heliothis zea, the apodeme arising from the frontal sulcus; an internal ridge thought to be an invaginated frons.

FRONTAL GANGLION - A small globular ganglion of the stomodeal nervous system lying above the oesophagus and in front of the supraoesophagial ganglion.

FRONTAL LUNULE - In the adult Musca domestica, a descriptive term for a triangular sclerite lying at the apex of the frons and above the antennal sockets.

FRONTAL MUSCLE - A muscle arising from the ental surface of the frons and associated with the pharynx, in Heliothis zea, one of the muscles associated with the cibarial pump.

FRONTAL SACS - In the larva of Musca domestica, sac-like invaginations lying behind the cibarial apparatus; contains the primordial cells for the frontal areas and appendages of the adult head.

FRONTAL SULCUS - In the larva of Heliothis zea, a deep groove or suture of the head giving rise to the frontal ridge; what appears to be a coronal suture of an incorrectly identified ecdysial suture.

FRONTAL SUTURE - In the adult of Musca domestica, the triangular suture margining the frons and invaginated into the ptilinum.

FRONTOCLYPEUS - A facial area combining the frons and the clypeus in the absence of an epistomal suture.

GANGLION (pl. GANGLIA) - A nerve center comprised of the terminal axons of the afferent nerves, the association neurons, and the nerve cells of the efferent nerves.

GENA (pl. GENAE) - The cranial area identified as the cheeks; specifically, the cranial area below and sometimes before the compound eyes.

GENERALIZED - Primitive in form with structure occurring early in an animal's phylogenetic history; primitive.

GENITAL PORE - External orifice of the median oviduct or the ejaculatory duct.

GLAND CELL - One of the modified epidermal cells evolved for a secretory function.

GLOSSA (pl. GLOSSAE) - An endite of the labium; usually a median pair of lobes at the apex of the prelabium; in the adult of Apis mellifera, the median tube or tongue of the proboscis.

GNATHOCEPHALON - A hypothetical posterior division of the definitive head bearing the gnathal metameres and the mandibulate appendages.

GULA - The ventral sclerite of the prognathous head bounded by the postoccipital (or gular) suture; probably a sclerotized expansion of the ventral cervix.

GULAR SUTURE - A descriptive name for the postoccipital suture; in the absence of a clearly identifiable postoccipital suture, the suture bounding the gula.

HAUSTELLATE - Insects with sucking mouth parts.

HAUSTELLUM - The median, tubular region in the mouth parts of the adult Musca domestica.

HEAD - The tagma which is the center of sensory perception and food ingestion; the region bearing the functional mouth as in the larva of Musca domestica.

HINGE PLATE - In the adult Musca domestica, a descriptive term for a sclerite posterior to and articulating with the clypeus.

HOLOPTIC - A descriptive term for Musca domestica relative to the distance of separation between the compound eyes; in the male Musca domestica as compared with the female, the eyes are set close together.

HYOID SCLERITE - In the mouth parts of the adult Musca domestica, a small sclerite lying in the narrow channel between the food canal and the cibarium.

HYPOGNATHOUS - A condition of the head where the mouth parts are in a pendent position and the frontal areas are directed anteriorly.

HYPOPHARYNGIAL LOBE - A membranous lobular expansion of the hypopharynx before the mouth in Apis mellifera.

HYPOPHARYNGIAL SUSPENSORIA - Apodemes which activate the anterior portion of the hypopharynx.

HYPOPHARYNX - the median lobe or tongue which in the mandibulate mouth parts lies before the mouth; forms the floor of the cibarium on its dorsal aspect and the roof of the salivarium on its ventral aspect.

HYPOSTOMAL SCLERITE - An H-shaped sclerite in the larva of Musca domestica articulating with the cibarium on its posterior aspect and anteriorly with the mouth hook; serves to support the salivary duct and provides a salivary channel on its dorsal surface.

INSTAR - Any of the stages in the development of a holometabolous larva; the first instar is the physical form of the larva between its eclosion from the egg and its first molt, etc.

INTEGUMENT - The covering or envelope enclosing the animal's body; in insects, the cuticula.

INTERSEGMENTAL MEMBRANE - The infolded cuticula between metameres, usually soft and flexible.

INVAGINATE - An infolding cf the cuticula; apodemes and intersegmental membranes are invaginations of the body wall.

JUGUM (pl. JUGA) - A descriptive term used in Oncopeltus fasciatus to identify sclerites laterad of the anteclypeus or tylus; the mandibulate plate since the apodeme associated with the mandibular muscles arise from these sclerites.

LABELLUM (pl. LABELLA) - The fleshy, pad-like lobes at the distal end of the proboscis in adult Musca domestica, possibly derived from labial palps; the spoon-shaped sclerite at the distal end of the glossa in Apis mellifera.

LABELLAR SCLERITE - An apodeme in the proboscis of adult Musca domestica which articulates the labella.

LABIAL GUTTER - The dorsal groove in the labium which accommodates the stylets, specifically the dorsal groove in Musca domestica; the dorsal gutter of Oncopeltus fasciatus.

LABIAL-MAXILLARY COMPLEX - A partial or complete fusion of the labium and maxillae to form a complex such as in the mouth parts of the larvae of Phyllophaga rugosa and Heliothis zea.

LABIAL PALPS - The palpi of the labium; the telopodite of the labial appendages.

LABRAL APODEME - An apodeme upon which the muscles articulating the labium are inserted.

LABRAL STYLET GROOVE - In the mouth parts of Oncopeltus fasciatus, a groove on the ental surface or the labrum which accommodates the basal stylets.

LABIUM - The most posterior of the gnathal appendages; a composite structure forming the floor of the mouth cavity in mandibulate mouth parts and appendages which are variously modified in haustellate forms.

LABRUM - A cranial sclerite articulating at its proximal margin with the clypeus, and forming an upper lip for the mouth cavity.

LARVA (pl. LARVAE) - The immature stages of the Holometabola, or insects with a complete metamorphosis, following eclosion and preceding pupation.

LATERAL PLATES - The principal articulatory sclerites of the cervix; a hinge sclerite usually composed of a DORSAL LATERAL PLATE articulating with the postocciput and a VENTRAL LATERAL PLATE articulating with the episternum.

LATERAL SCLERITE - Paired sclerites occurring on the lateral margins of the hypopharynx in Leucophaea maderae.

LIGULA - The anterior portion of the prementum of the labium; a term usually used to describe the anterior area of the labium when the glossae and paraglossae are absent.

LINGUA - A term applied to the fleshy distal portion of the hypopharynx.

LONGITUDINAL SUTURE - The lateral, longitudinal invagination of the abdominal body wall demarcating the tergum and sternum.

LORAL ARM - An apodeme articulating with the basal aspect of the hypopharynx.

LORUM - A descriptive term in Apis mellifera for a Y-shaped sclerite forming a labial-maxilla yoke, its arms articulating with the cardo and the stem with the postmentum.

MAGGOT - The common, descriptive term for the immature or larval stages of Musca domestica.

MANDIBLE - The most anterior of the gnathal appendages; in the mandibulate forms, the jaws employed for cutting, crushing and grinding solid foods.

MANDIBULAR APODEME - Apodemes attached to the mandible upon which either abductor or adductor muscles are inserted.

MANDIBULAR PLATES - Sclerites laterad of the anteclypeus or tylus in Oncopeltus fasciatus; the jugum cf descriptive entomology.

MANDIBULAR SCLERITE - A cranial sclerite in the adult of Heliothis zea laterad of the proximal proboscis; a sclerite that appears to be a remnant of the mandibles.

MANDIBULATE - A term used to describe mouth parts composed of a mandible-maxilla-labium complex; referable to an animal with chewing mouth parts.

MAXILLA (pl. MAXILLAE) - The second of the post-oral gnathal appendages; appendages of the mandibulate type of mouth parts serving to augment the mandibles and as an aid in the ingestion of food; variously modified into a proboscis in the haustellate forms.

MAXILLARY APODEME - An apodeme associated with the articulatory muscles of the maxillae.

MAXILLARY ARTICULATION - A groove or flange on the posterio-ventral edge of the cranium upon which the maxillae articulate.

MAXILLARY PALP - The palpi of the maxillae; the telopodite of the maxillae.

MAXILLARY PLATE - A descriptive term in Oncopeltus fasciatus for a sclerite lateral and ventral of the proximal proboscis; a sclerite lying below the jugum and above the buccula.

MENTUM - A term applied to the distal portion of a divided postmentum.

METAMERE - Any of the principal subdivisions of an insect's body; in the prototype, a functionally independent unit in the worm-like animal comprised of a prostomium, 18 subdivisions or metameres, and a periproct.

METAMERISM - A descriptive term used to identify an animal with a body composed of ring-like subdivisions or metameres.

METAMORPHOSIS - The post-embryonic developmental process; the post-embryonic development required before attaining the imaginal or sexually mature stage.

MICROTRICHIA - Minute, hair-like spines of a non-cellular composition; fixed, exocuticular outgrowths of the body wall, the aculei of descriptive entomologists.

MOLA - The posterior, grinding area of the mandible.

MOLAR AREA - The grinding area of the mandible; the mola.

MONOCONDYLIC ARTICULATION - A single point of articulation of an appendage; a single articulation point compared with the hinge-like, dicondylic articulation.

MORPHOLOGY - The science or study of the functional form of an animal.

MOUTH - The anterior orifice of the oesophagus; frequently refers to the apparent external opening of the digestive tract; technically, not the oral cavity or the passage to the cibarium and pharynx.

MOUTH HOOK - The hook-shaped, oral sclerlte ln the maggot employed as a rasping structure.

MOUTH PARTS - The organs of ingestion; including the modified ambulatory structures as the mandibles, maxillae and the labium, and such cranial lobes as the labrum and hypopharynx; applied to the ingestive apparatus of mandibulate and haustellate forms, and includes the specialized oral structures of the maggot.

MULTICELLULAR PROCESS - Any of the evaginations or invaginations of the body wall including the epidermis; includes apodemes as well as external protuberance 

NONCELLULAR PROCESS - A protuberance composed entirely of cuticula; not an evagination involving the epidermis.

NYMPH - The post-embryonic forms of insects with a gradual or paurometabolous metamorphosis; the sexually immature forms of such Exopterygota as Leucophaea maderae or Oncopeltus fasciatus.

OESOPHAGUS - The anterior undifferentiated stomodaeum or fore gut of an insect leading from the mouth to the mesenteron; or if the stomodaeum is differentiated, that anterior portion from the mouth to the crop, or proventriculus, etc.

OCCIPITAL FORAMEN - The posterior opening of the cranium or head capsule serving as a passageway for the gut, tracheae, ventral nerve cord, etc. into the lumen of the head; that portion of the head margined by the postocciput.

OCCIPITAL SUTURE - The suture or demarcation of the occiput.

OCCIPUT - A posterior sclerotized region of the head set off by an occipital suture and lying between the vertex and genae and the postocciput.

OCELLUS (pl. OCELLI) - Small, round to ovoid photo receptors with a single dioptric apparatus; "simple" eyes that may occur in clusters or as a group of 3 or 2.

OCULAR SCLERITE - A peritreme or sclerotic rim encircling the compound eye.

OCULAR SUTURE - A suture demarcating the sclerotic rim or ocular sclerite of a compound eye.

ONTOGENY - The developmental history or embryological development of an individual.

ORAL CAVITY - The mouth; an anterior expansion of the oesophagus.

ORAL FLAP - A membranous, fleshy lobe at the posterior, mesal angle of the mandible.

OVIPOSITOR - Appendicular structures in the female arising from the eighth and ninth metameres variously modified for the handling and deposition of eggs; a modification of the caudal metameres for the deposition and insertion of eggs.

PALPIFER - A sclerite of the maxilla which bears the maxillary palp.

PALPIFORM - Any appendage or protrusion that is segmented and resembles a palpus such as the maxillary palp.

PALPIGER - A sclerlte of the labium which bears the labial palp.

PAPILLA (pl. PAPILLAE) - A minute, tubular protrusion usually sensory in function.

PARAGLOSSA (pl. PARAGLOSSAE) - An endite of the labium occurring in position to the outside of the glossa.

PARANOTAL LOBES - The flap-like evaginations of the lateral margins of the tergum in fossil forms which may have been the precursors of wings.

PERIPROCT - The anus-bearing subdivision of the abdomen; the 20th division of a hypothetical prototype bearing the anus.

PERITREME - A ring-like sclerite or protuberance encircling a structure such as a seta or eye.

PHRAGMA - The apodemes arising from the tergum of the thorax which produce an internal flange for muscle attachment.

PHYLOGENY - The genealogy of a species; tracing the development or evolutionary history of an individual through such categories as genus, family, order, etc.

PILIFERS - A descriptive term for a pair of setaceous flaps occurring on the proximal margins of the proboscis in the adult of Heliothis zea; possible remnants of mandibles.

PIT - A circular opening in the cuticula leading to the alveolus of a sensory seta or to the pore canal of a dermal gland.

PLEURA - Collectively the sclerites that comprise the lateral aspect of the thorax.

POISON CELL - A modified epidermal cell capable of secreting an urticating fluid into the lumen of a seta.

POSTCLYPEUS - The sclerotized proximal portion of the clypeus where this sclerlte is divided into sclerotized and membranous areas.

POSTERIOR CONDYLE - Usually a ball-shaped protuberance on the posterior margin of the mandible which articulates with a cranial groove; the primary mandibular articulation.

POSTERIOR TENTORIAL BRIDGE -The posterior aspect of a typical TT-shaped tentorium; the united arms of the posterior tentorial invaginations.

POSTERIOR TENTORIAL PITS - The points of the cranial invaginations which produce the posterior aspect of the tentorium.

POSTGENA (pl. POSTGENAE) - The posterio-ventral aspect of the head; frequently the ventral aspect of the occiput.

POSTGENAL INFLECTION - In Apis mellifera, a ventral depression of the head cavity which accommodates the caudal aspect of the proboscis.

POSTLABIUM - The basal or caudal, undivided portion of the labium articulating with the cervix in the hypognathous head.

POSTMENTUM - The postlabium.

POSTOCCIPITAL RIDGE - A broad flange-like apodeme produced by an invagination at the postoccipital suture.

POSTOCCIPITAL SUTURE - A suture demarcating the postocciput, and the line of invagination for the postoccipital ridge.

POSTOCCIPUT - The most posterior sclerite of the head, usually a collar encircling the occipital foramen; the sclerite articulating with the labium in primitive forms.

PREORAL CAVITY - The cavity of the head formed by the mandibulate mouth parts preceding the cibarium and the mouth.

PRELABIUM - The anterior portion of the labium bearing the palps and endites; the prementum.

PREMENTUM - The prelabium.

PRESTOMAL TEETH - In the mouth parts of adult Musca domestica, five sclerotized plates anchored on the discal sclerite; apparently used for scraping a food medium.

PRESTOMUM - A functional mouth in the labella of Musca domestica; the opening on the anterior aspect of the labella margined by the discal sclerite.

PRETARSUS - The most distal but incomplete tarsal segment of the leg usually retracted within the fifth tarsus; bears the claws and other terminal structures.

PRIMARY ANTENNAE - Antennae borne by the prostomium of the theoretical prototype.

PRIMARY SETAE - Those setae of a naked larva, or the prominent bristles, which are fixed and constant in position.

PRIMITIVE - Ancient in occurrence; a structure which appeared early in the phylogenetic history of a species.

PRIMORDIAL MOUTH HOOK - A formative mouth hook in the maggot, incomplete in development but recognizable as the developing hook of a subsequent instar.

PROBOSCIS - The common term used to describe the entire haustellate mechanism; a sucking tube or prominent structure of the sucking apparatus such as the labium of Oncopeltus fasciatus.

PROGNATHOUS - A modification of the head which permits the forward direction of the mouth parts and a rotation of the facial region to a dorsal position.

PROSTHECA - The mesal, fleshy protuberance of the mandible of Phyllophaga rugosa midway between the mola and the tip; possibly a remnant of an endite similar to the lacinia of the maxilla.

PROSTOMIUM - The head or anterior subdivision of the theoretical prototype bearing the eyes, antennae and mouth.

PROTOCEPHALON - A combined head structure of a prototype involving the prostomium and the first post-oral metamere.

PROTOCEREBRUM - The most anterior (or dorsal) lobe of the supraoesophagial ganglion which innervates the compound eyes and ocelli.

PROTOTYPE - A primitive, theoretical form which was the ancestor or precursor of a definitive form.

PROTRACTOR MUSCLE - Muscles which project an appendage or structure away from the central body mass.

PROXIMAL - Anything that is closest to the central body mass; basal.

PTILINUM - An invaginated and emersible sac in the head of adult Musca domestica which can be expanded thereby increasing the size of the head and assisting the insect in escaping from its pupal case by bursting the puparium.

RETRACTOR MUSCLES - Any muscle system which draws or pulls a structure within or towards the main body mass or from its extended position.

ROD - In the mouth parts of Apis mellifera, a sclerotized U-shaped or channeled structure normally enclosed within the glossa.

ROSTRUM - The fleshy base of the proboscis in the adult Musca domestica.

SALIVA - The secretion of the salivary glands which primarily serves as a digestive substance (contains enzymes) but which may also serve as an anticoagulant. or be modified so that it will harden into a silk.

SALIVARIUM - A cavity, formed by the ventral surface of the hypopharynx and the ental surface of the labium, into which saliva is secreted; in some forms, this cavity may be enclosed to form the vessel of a salivary pump.

SALIVARY GLAND - The tubular glands which secrete saliva or a substance which will form silk upon drying as in the holometabolous larvae.

SCALE - A modified seta which is flat or spatulate in shape.

SCLERITE - An area of the integument or a segment of an appendage which is hard or plate-like and is usually bounded by sutures which may be flexible infoldings of the cuticula.

SCLEROTIN - A polymerized, tanned protein which imparts the hard and horny characteristics of the exocuticle.

SCLEROTIZED - Cuticula impregnated with a polymerized, tanned protein; a hard, inflexible portion of a structure or integument.

SCLEROTIZATION - The process of hardening the cuticula.

SECOND ANTENNA - A theoretical second pair of sensory structures which may have occurred on the first post-oral metamere.

SECONDARY SETAE - Setae which serve as clothing hairs usually abundant in number and which do not occur in a uniform pattern.

SENSORY NERVE CELLS - The secondary or afferent nerve cells which receive stimuli and transmit such stimuli to the nerve centers.

SETA - A hollow, unicellular protuberance of the body wall secreted by a modified epidermal cell or trichogen cell; usually a hair or bristle like structure.

SETAL MEMBRANE - The thin sheet of cuticula secreted by a tormogen cell surrounding the base of a setae and serving as a floor in the alveolus.

SEXUAL DIMORPHISM - A difference in characteristics, coloration or physical form of a structure in the opposite sexes of a particular species.

SITOPHORE - A shallow channel on the dorsal, proximal surface of the hypopharynx before the mouth.

SPECIALIZED - A highly evolved form or structure; a modification occurring relatively late in the evolutionary history of an individual.

SPINES - Non-cellular protuberances of the body wall which are hard and inflexible and composed of exocuticle; these may be hair-like and resemble setae, but are not hollow and do not arise from an alveolus.

SPINNERET - A modification of the salivarium for the storage, ejection and manipulation of silk.

SPUR