Glossary of Phasmid Terms


Term Explanation
Abdomen The third of the three main parts of an insect's body.
Abdominal segments The segments making up the abdomen are numbered from front to back. Traditionally Roman numerals have been used to number the segments but the use of Arabic numerals is becoming increasingly common. The first, tenth and eleventh segments have specific names: 'Median segment', 'Anal segment' and 'Lamina supraanalis'.
Acanthotaxy The naming of spines on the body and head. This is particularly useful for members of the Heteropteryginae; the spines were described and illustrated by Rehn & Rehn (1938).
Ala The hindwing. This is attached to the anterior of the metanotum and is divided into the leathery costal region and the folding anal region.
Anal process A process projecting from, and part of, the anal segment. The processes are usually paired although the two may be of unequal size (e.g. in Presbistus spp).
Anal region The folding part of the Phasmid's hindwing. This is often transparent or translucent, and only rarely opaque.
Anal segment The tenth abdominal segment. In most species this is the last full-sized segment but in females of some species the 11th segment may be large.
Antenna One of a pair of jointed sensory structures arising from the front of the head. A feeler.
Appendicular ovipositor An ovipositor formed by elongated ovipositor valves. It projects beyond the end of the abdomen.
Archedictyon A network of non-directional veins in the costal region of the wing or in the elytron. It is these veins which make the elytron and costal region of the hindwing thicker and stiffer than the anal region of the hindwing.
Areola A sunken area on the ventral surface of the apex of the tibiae. This depression is roughly triangular. This feature is used to split Phasmids into two groups: the Areolate which have the sunken area and the Anareolate which do not.
Arolium A pad between the claws (ungues) of the pretarsus.
Arthropod An animal with jointed limbs composed of tubular sections of hard external skeletal material. A member of the phylum Arthropoda.
Autotomy A defensive reaction which results in the automatic shedding of a limb.
Binnenkörper A hard sclerotization found in the genitalia of some female Asciphasmatinae; may protrude from the left side of the operculum. The function is unknown.
Body length The combined length of head, thorax and abdomen, including the operculum. Some authors seem to have excluded the operculum from the body length, so where the operculum extends beyond the end of the anal segment it is preferable to state clearly whether the operculum is included in the body length.
Capitulum A raised structure on the operculum of the egg (not present in all species).
Carina A ridge or raised line typically along the leg, or centre line of the body.
Cercus Paired appendages attached to the anal segment. They may project beyond the end of the abdomen or be hidden underneath. In a few cases they are enlarged leaf-like structures.
Chitin The basic material from which both the hard skeleton and flexible membranes of an arthropod body are formed.
Class One of the groups into which a phylum is divided.
Collar The part of the capsule of an egg which surrounds the operculum. This is often a narrowing (and occasionally an elongation) of the capsule.
Compound Eye An eye composed of many individual optical units.
Costal region The anterior portion of the hindwing. This is thickened, opaque, and does not fold. It is the part of the hindwing which is uppermost when the wings are folded.
Coxa The uppermost section of an insect leg.
Dentate See 'Toothed'.
Dimorphism Occurs in two distinct body types. In a sexually dimorphic species the males and females are morphologically different.
Dorsal Describing the upper surface of a body.
Dorso-anterior carina A carina on the front, upper corner of the femur or tibia.
Dorso-posterior carina A carina on the back, upper corner of the femur or tibia.
Ecdysis The shedding of the skin which takes place as an insect grows
Elytron The forewing. Attached to the posterior of the mesonontum. [Tegmen].
Femur The upper of the two main parts of an insect leg, above the 'knee' joint.
Foramen See 'Pronotal foramen'.
Gonapophysis Appendages on the female's abdomen which are usually hidden by the operculum, but in some species they form part of the appendicular ovipositor and are clearly visible. [Ovipositor valves].
Granular See 'Granulose'.
Granulose Covered in small granules; generally circular, and height is less than the diameter. [Granular].
Haemocoel A body cavity filled with blood.
Hindwing Attached to the anterior of the metanotum. The term hindwing (or hind wing, or hing-wing) is usually used. The alternative, "ala", is rarely used. [See 'Wing', 'Costal region', 'Anal region'].
Instar A distinct stage in the life-history of an insect, separated from the previous stage by an ecdysis.
Labium The lower lip, equipped with a pair of palps.
Lamella A thin sheet. Often used to refer to a thin sheet or lobe along the carina of a leg, typically running the whole length of the femur or tibia (frequently found in Lonchodinae).
Lamina subgenitalis The plate covering the genital opening. Rather an out-dated term. [Subgenital plate, Operculum of female, Poculum of male].
Lamina supraanalis The 11th tergite (11th dorsal abdominal segment). Absent in males but can be seen in some females. It may be quite long but is more often minute or absent. [Supra-anal plate].
Mandible The hard biting jaw.
Maxilla The softer jaw which lies behind the mandible, equipped with a palp.
Medi-ventral carina A carina in the middle of the ventral face of the femur or tibia.
Median segment The first abdominal segment. This is fused with the metanotum to varying degrees. In some instances it is indistinguishable from the metanotum.
Median sternite The sternite of the median segment (indistinguishably fused with the metasternum in most cases).
Median transverse groove An indentation running across the pronotum, usually more or less in the middle. It is particularly noticeable in some groups, e.g. Dares, but in many groups can only be seen with magnification. It marks the position of the sulcus, the joint between the two plates which make up the pronotum. Sometimes just referred to as the 'sulcus'.
Mesonotum The upper surface of the mesothorax.
Mesothorax The second section of the thorax. The middle legs and elytra are attached to the posterior of this segment.
Metamorphosis A relatively sudden change in body form on maturing.
Metanotum The upper surface of the metathorax.
Metathroax The third section of the thorax. The hindwings are attached to the anterior, and the hind legs to the posterior of this segment.
Micropylar plate A distinct plate on the side of the egg, in which the micropyle is situated.
Micropyle A small hole in the side of the egg.
Notum A tergum of a thoracic segment, i.e. a dorsal plate of the thorax [See 'Pronotum', 'Mesonotum', 'Metanotum'].
Nymph An immature insect, looking rather like the adult except for its lack of wings.
Ocellus A simple eye, found in the middle of the forehead.
Opercular angle The angle that the operculum of an egg makes with the longitudinal axis. This may be either positive or negative.
Operculum The lid of an egg.
Operculum Covering of genital opening of the females (the term has also been used for males by some authors but should be restricted to females; 'Poculum' should be used for males). [Lamina subgenitalis; Subgenital plate].
Order One of the groups into which a class is divided.
Orthopterous Referring to insects which have toughened forewings, as in the order Orthoptera.
Ostium A hole opening into the heart.
Ovipositor A device for egg laying, found in many species which push eggs into soil, cracks or plant tissues. It is formed either by an elongated lamina supraanalis and elongated operculum (an oviscapt); or by elongated valves and the operculum (an appendicular ovipositor).
Oviscapt An ovipositor which is formed by elongation of the operculum (8th sternite) and lamina supraanalis (11th tergite). Examples occur in Heteropterygini, Obrimini, some Eurycanthinae, and some Necrosciinae. It is analogous to that found in several Dipteran groups where the oviscapt is formed by a modified 7th sternite and 7th tergite.
Palp A small antenna-like structure attached to the mouth parts.
Parthenogenesis The production of young from unfertilised eggs.
Pectinate Comb-like. The term is used to refer to the serrated ungues of Aschiphasmatinae.
Phasmid A general name for any of the Stick Insect group. Derived from the name of the order Phasmida.
Phylum One of the major groups into which the animal kingdom is divided.
Plantula A small pad underneath the tarsus
Pleurite A pleural sclerite, i.e. a lateral plate. One on the side of the body between the tergum and sternum. They are most commonly seen on the thorax and may be very large and distinct in some groups, e.g. on the thorax of Heteropteryginae.
Poculum The covering of the male genital opening; the 9th sternum. Often referred to as the male operculum, but the use of poculum is preferable since it cannot be confused with the female operculum. [Lamina subgenitalis, Subgenital plate].
Polar body A mound on the egg at the opposite end to the operculum.
Praeopercular organ An organ on the 7th sternite of females, used during copulation. It is usually composed of one or more bumps, ridges or flaps. It is not present in all species. [Preopercular organ].
Preopercular organ See 'Praeopercular organ'.
Pretarsus The distal segment of the tarsus, i.e. the claws (ungues) and arolium at the end of the 5th tarsomere (3rd tarsomere in Timema).
Prognathous Jaws face forward.
Pronotal foramen A distinctive opening on the anterior of the pronotum, used as a diagnostic character of the tribes of Heteropteryginae (Rehn & Rehn, 1938).
Pronotum The upper surface of the prothorax.
Prothorax The first segment of the thorax. The forelegs are attached to this segment.
Punctate Covered with many small pits (used in description of the surface structure of eggs).
Regeneration The ability to regrow a lost structure.
Rugose Wrinkled, covered in small ridges.
Rugulose Minutely rugose, finely wrinkled.
Scabrose See 'Scabrous'.
Scabrous Rough; irregularly and roughly rugose; possessing short sharp projections of wrinkles.
Sclerite A hard plate of the body. These may be given more precise names depending on where they are on the body, i.e. tergite, sternite.
Segment One of a series of similar parts in the main body of an insect, often indicated by grooves or joints in the outer surface.
Setose Covered in setae; covered in stiff hairs.
Spermatophore A small sac containing sperm used by some male insects during mating.
Spiracle A hole through which air is taken into the body.
Sternite A ventral plate; a hardened plate which makes up part (or all) of the sternum.
Sternopleurite A lateral plate on the ventral surface of the body, these are rarely evident externally.
Sternum The ventral part of a segment including sternites and sternopleurites. Often sternopleurites are not evident, in which case the sternum may consist of a single sternite.
Subgenital plate A plate covering the genital area. [Lamina supragenitalis; Operculum; Poculum].
Supra-anal plate The 11th abdominal segment [Lamina supraanalis].
Tagma One of the main divisions of the insect body - head, thorax or abdomen.
Tarsomere A segment of the tarsus. There are five segments in all Phasmids except Timema which only have three.
Tarsus The 'foot' of an insect, usually divided into five parts.
Tegmen The forewing. Use of this term seems to have deceased with a corresponding increase in the term 'elytron' in recent years.
Tergite A dorsal sclerite; a hardened plate on the dorsal surface of the body which makes up part (or all) of a tergum.
Tergum The dorsal part of any segment. Although the term applies to all segments, notum is often used to refer to the thoracic terga.
Terminalia The external structures which aid in mating and egg laying.
Thorax The middle part of an insect body bearing the legs and the wings.
Tibia The lower of the two main parts of an insect leg below the 'knee' joint.
Tooth A tubercule in which the height is greater than the diameter; a short blunt spine.
Toothed Bearing numerous teeth. [Dentate].
Trachea A breathing tube.
Trochanter A minute section of insect leg lying between coxa and femur.
Tuberculate Covered in tubercules. Finely tuberculate is generally considered the next stage after granulose i.e. more strongly projecting than granulose.
Tubercule A blunt or irregularly topped structure, not pointed like a spine. Usually small but the term is also used to refer to large wart-like structures, often of an irregular shape.
Ungues The claws of the pretarsus.
Ventral Describing the lower surface of a body.
Ventro-anterior carina A carina on the front, underside corner of the femur or tibia.
Ventro-posterior carina A carina on the back, underside corner of the femur or tibia.
Verrucose Covered in irregularly shaped lobes or wart-like protuberances.
Vomer A moveable sclerotization on the 10th abdominal segment of the male, usually more or less triangular in shape and used during copulation [Vomer subanalis].
Vomer subanalis See 'Vomer'.
Wing The terms elytron or tegmen are almost always used when referring to the forewing of a Phasmid. The term hindwing is usually used in preference to ala. If the term wing is used on its own it usually refers to the hindwing since in most Phasmids the forewing is relatively insignificant. [See 'Elytron', 'Tegmen', 'Ala', 'Hindwing'].