These muscles contract to produce an upward thrust. Pest of domestic animals and plant: Some insects affect the health of domestic animals and their quality. They are called insects. Hexapoda (Insecta) A class of the phylum Uniramia comprising about a million known species of arthropods (many more are thought to exist).They are distributed worldwide in nearly all terrestrial habitats. This stored energy reaches a maximum at the critical point. Blood is not important in gas transport. The tilt of the wing must be controlled. The stretching of longitudinal flight muscles during the upward beat of the wing initiates the contraction of these muscles. Alarm pheromones: These are used to warn other individuals of danger. Hexapoda 1. Members of this order are diverse in behaviour and appearance, with wingless larvae that are very different from their delicately-winged adult forms. The lower the leaf stability index for a given terminal taxon is, the less stable is its phylogenetic position. Caste-regulating pheromones: These are used by social insects to control the development of individuals in a colony. It is sensory in function. A few pheromone molecules of another individual can produce enough response. Pdx, she/they. Orthoptera: pictures (105) Orthoptera: sounds (10) Superfamily Grylloidea. Their bodies are divided three sections - the head, the thorax, and the abdomen. Therefore, molt is stopped in most of adult insects. , The non-insect hexapods have variously been considered a single evolutionary line, typically treated as Class Entognatha, or as several lines with different relationships with the Class Insecta. Similarly, the predatory insects select moving prey. Phermones fall on a chemoreceptor. Ametabolous metamorphosis (a, without + metabolos, change): In this case, primary differences between adults and larvae are body size and sexual maturity. Sub-esophageal ganglion: Connectives join the supraesophageal ganglion to the sub-esophageal ganglion. Table 1. There are so many insects and they are so important that they are described in greater detail below. Later, insects started using these fixed lobes for gliding from the top of tall plants to the forest floor. Subphylum Hexapoda ∼5+ million: Insects, springtails, bristletails, etc. Subphylum: Hexapoda (Insects) 2. Social behavior is highly developed in the bees, wasps and ants and in termites. (2016):, An incomplete possible insect fossil, Strudiella devonica, has been recovered from the Devonian period. It destroyed the citrus industry in California in twenty year. nida, Hexapoda (so-called "true insects"), Centipedes, and Millipedes. Class – 2 : Entognatha. hexapoda Artist, scientist, snowflake, misanthropic sjw. Various ions are actively transported into the tubules. No cells are more than 2 or 3 pm from a tracheoles. Insects also give pleasure to those who collect them and enjoy their beauty. & Bergström J., 1997. Compound eyes consist of an up to 28,000 receptors called ommatidia. The eh sails and puperium are the last larval exoskeletons. 3. Two endocrine glands are present in the subesophageal ganglion. They change the shape of the exoskeleton for both upward and downward wing strokes. 4. A single nerve impulse can cause approximately 50 cycles of the wing. Hexapoda Classe Insecta Sous-classe Pterygota Infra-classe Neoptera Super-ordre Dictyoptera Super-ordre Polyneoptera Ordre Blattodea Latreille , 1810 Les cafards ou blattes ou encore cancrelats appartiennent à l' ordre des blattoptères (Blattodea), dont font aussi partie les termites . In some cases, however, the number of legs has been evolutionarily reduced, or the legs have been highly modified to accommodate specific conditions, such as endoparasitism. This fossil may help to fill the arthropod gap from 385 million to 325 million years ago. This folds allows the abdomen to expand when the insect is gorged. Diplopoda. Population density, temperature and humidity also influence reproductive activities. Butterflies, dragonflies and grasshoppers are examples of insects with a synchronous flight mechanism. They leave the hive and mate with queen. Ø Segment 6 bears the labium which forms the lower lip of mouth. lnsects can walk, run, and jump. Head: Head bears a single pair of antennae. 2. An isomer of a pheromone is ineffective in initiating a response. There are complex interactions between internal and external environmental factors. The insects are capable of some learning and have a memory. The subphylum Uniramia is divided into three classes: Onychophora (velvet worms), Hexapoda (insects), and Myriapoda (‘pedes, both centi- and milli-). These legs have larger muscles. A running cockroach reaches speeds of about 5 km/hour. Function of insect pheromones. Simple flapping of wings is not enough for flight. mouth parts, compound eve and zero, two, or three ocelli. Bees that feed once at artificially scented feeders choose that odor in 90% of feeding trials. This primary group was set up to indicate the residuum of Cuvier's Articnlata when his class Annelides (the modern Cheefcopoda) was removed from that " embranche-ment." Insects have high reproductive potential. Scientific classification; Kingdom: Animalia: Phylum: Arthropoda (unranked): Pancrustacea: Subphylum: Hexapoda Latreille, 1825: Classes & Orders; Class Insecta (insects) Class Entognatha. This process is called shivering thermogenesis.Thermogenesis can raise the temperature of thoracic muscles from near 0 to 30 oC. the bees recognize flower like objects by their shape and ability to absorb ultraviolet light. ... and the lower lip contains a pair of maxillae. Nuclear protein data supports the monophyly of Hexapoda, the clade uniting entognath and ectognath insects. Queen releases a pheromone. Aggregation pheromone: These are produced to attract individuals to feeding or mating sites. These veins increase the strength of the wings. They are called heterotherms. Morphology and anatomy of adults: Antennae - giand.it", "How do insects breathe? Eg., Julus, Scolopendra. 2. Tell a friend about us, add a link to this page, or visit webmaster’s page for free fun cheerful. Malpighian tubules end blindly in Hindgut the haemocoel: They open in to the gut at the junction of the mid gut and the hindgut. Periodically, the dissolved bicarbonate ions are converted back into carbon dioxide. Although zoologists debate their possiblehomology (common ancestry). Example. But it seems much faster when one person is trying to catch it. All insects warm themselves by basking in the sun or resting on warm surfaces. The vedalia beetle was brought to the United States in 1888 and 1889. Therefore, the regulation of daily rhythms. It is then transferred into the gut. Different insects have developed different mechanisms of development. Recent evidence suggests that the closest relatives to Hexapoda are Crustacea (Giribet et. Polarized light is used for navigation and orientation. Insecta: information (1) Insecta: pictures (4548) Insecta: specimens (106) Insecta: sounds (13) Order Orthoptera. 3. It escapes through the tracheal system. These outgrowths protected the legs or spiracles. Hexapods have bodies ranging in length from 0.5 mm to over 300 mm which are divided into an anterior head, thorax, and posterior abdomen. The flea jump and elastic energy is stored in the exoskeleton. The muscles that control wing tilting are attached to sclerotization plates at the base of the wing. 3. In particular, the Diplura may be more closely related to the Insecta than to the Collembola (springtails) or the Protura. Mishra 1 ... silkworm miRNAs which is significantly lower than that in fruit fly (152). Strepsiptera – Classes (2): Ils comprennent tous les insectes ainsi que d'autres classes comme les protoures, les diploures et les collemboles. Insects are used in teaching and research. Most insects have ventilating (exchange of gases) mechanisms. Insects have segmented … 4. Therefore, a vacuum is created. It reduces respiratory water loss. They care for the larvae. Cependant en 2014 la description d'un nouveau genre, Khasips, comprenant trois espèces , a conduit D. S. Kopylov à confirmer la place des Archaeocynipidae au sein de la super-famille des Cynipoidea : A mechanism is also required to bring males and females together at appropriate times. The Class Insecta, or the slightly larger Superclass Hexapoda (which additionally includes the orders Collembola, Protura and Diplura), is the world's most species-rich group of organisms, with about 1 million described species. Now worker again feed the royal jelly to several female larvae. 2. Some variations are present in these moot parts for sucking or siphoning plant or animal fluids. šest nogu) najveća je (prema broju vrsta) skupina člankonožaca te obuhvaća mnogobrojan razred kukaca (insecta) i razred Entognatha koji sadrži tri mnogo manje skupine beskrilnih člankonožaca: skokune (), bezrepce (), i dvorepce ().Skupina skokuna vrlo je rasprostranjena u kopnenom okruženju. Blattodea Blattodea Classification Règne Animalia Embranchement Arthropoda Sous-embr. Thermoregulation is the ability to maintain body temperatures at a level different from environmental temperatures. Therefore, the exoskeleton forms an arch. Fig: Honeyhees (Order Hymenoptera). 2. Drones: Drones develop from unfertilized eggs. Some insects are parasites and vectors of disease. Other insects contract abdominal muscles in a lump like fashion. Amongst the hexapods, the insects (Figure 1) are th… This final process is called emergence or eclosion. Fig: (a) Compound eye: (b) Structure of an ommatidium (c) Cross section through the rhabdom. 3. Silverfish have ametabolous metamorphosis. Insect transmit diseases like malaria, yellow fever, bubonic plague encephalitis, leishmaniasis, and typhus. The frequencies of 1,000 cycles per second are recorded in some midges. The body of an insect is divided into three tagmata: head, thorax, and abdomen. These cells are present beneath a single cuticular lens. It directly benefits humans. Cercope sanguin Cercopis vulnerata Un cercope sanguin. 3. Changes in metabolic rates, and pigment deposition. They are one of the most diverse groups, with over 750,000 species described so far (Tree of Life Web Project, 2002). Young workers work in the hive. Molting continues after sexual maturity. 2. The amount of royal jelly determines whether the larva will become a worker or a queen. The name Hexapoda denotes the presence of six legs (three pairs) in these animals as differentiated from the number of pairs present in other arthropods. Example: The female bee feed the larva with royal jelly. They are called insects. But some insects rely on a limited metabolic heat sources. It stimulates the sensory cells. Therefore, it is a very reliable cue for bees. Insects were the first animals to fly. It suggests that the wing have evolved from rigid, lateral outgrowths of the thorax. Following stages are formed during homometabolous metamorphosis: (a) Larva: Their immature is different from the adult in body form. Tympanal organs consist of a thin cuticular membrane. The amount of caste-regulating pheromone in the hive decreases with the death or aging of queen. Many different insects use phermones. Your email address will not be published. All of these mouth parts help in food handling. 4. The name "cockroach" comes from the Spanish word for cockroach, cucaracha, transformed by 1620s English folk etymology into "cock" and "roach". The older workers bring nectar and pollen. In aquatic insect, ammonia diffuses into surrounding water. The male usually transfer sperm into sperm receptacle of female. population ecology, and physiology. Required fields are marked *. It stores energy for the exoskeleton. Hexapoda. . It minimizes water lass. Animalia: information (1) Animalia: pictures (20673) Animalia: specimens (7109) Animalia: sounds (722) Animalia: maps (42) Unspecified Ecdysozoa. They produce wax and construct the comb from this wax. The trachea opens outside through spiracles. (d) The inner surface of metathoracic legs has setae, called the pollen comb. There is a most popular hypothesis about the origin of wing. Some insects have a series of gradual changes in their development. They are used in the study of genetics. This ganglion connects the mouth parts and salivary glands. The asynchrony between wing beat and nerve impulses is dependent on flight muscles. The endocrine system controls many physiological functions of insects. Long setae vibrate when certain frequencies of sound strike them. Insects are also able to cool themselves by moving in cool moist habitats. Most active in my stories and pay sites, DM for more info. In older classifications two Divisions were recognised in the Brachycera, the Orthorrhapha and Cyclorrhapha. These abilities play important roles in insect behavior. The thorax is deformed during a wing beat. They are fed by the workers. The head is fused with the thorax region known as the cephalothorax. Second group of muscles is attached dorsally and ventrally on the exoskeleton. Kingdom Animalia animals. Workers support, protect and maintain the colony. A Touch of Class… Photography: @hexapoda_photo linktr.ee/NationalResourcesList Cocoon is partially or entirely composed of silk. Ocelli consist of 500 to 1, 000 receptor cells. Insects cause pollination of 65% of all plant species. Lacewings belong to an ancient order of insects, Neuroptera. Insects have six legs, one pair on each of its three segments. If a bee is given nectar and pollen, it learns the odor of the flower. Insect Fossils Classification with Hexapoda: Tree of Life : Fossil Insect Classification Class Insecta and Subphylum Hexapoda . Thus there are decreases in the level of circaulating juvenile hormone. Insects also have an exoskeleton 1. For example, a newly queen develops in a honeybee hive . Animals: Arthropods-Hexapoda Ziser Lecture Notes, 2015.12 1615 1. Now it promotes the development of accessory sexual organs, yolk synthesis and the egg maturation. For example, the eggs of mosquitoes become mature after the female takes a meal of blood. Both adults and larvae are wingless. Hexapoda is then divided into two classes: the Entognatha includes primitively wingless hexapods such as springtails, while all the ‘true’ insects are subdivided into five major groups also know as superorders, the Apterygota, Palaeoptera, Polyneoptera, Paraneoptera and Endopterygota. Hexapods are named for their most distinctive feature: a consolidated thorax with three pairs of legs (six legs). The gametes dry quickly. Ecdysone initiates the reabsorption of the inner portions of the procuticle. Scrobipalpa heliopa (Lower, 1900) : Cohic (1950) [Statut pour Wallis et Futuna] Cohic, F. 1950. Many of the common insects we encounter on a daily basis—including ants, cockroaches, butterflies, and flies—are examples of Hexapoda. Members of the class Hexapoda are the most successful land animals. La classification des insectes, par conséquent la nomenclature entomologique et particulièrement les noms scientifiques des insectes ont subi de nombreux arrangements et modifications au fil des décennies. They are described in Table below. Thus the citrus industry recovered. Similarly, stretching during the downward beat of the wing initiates contraction of dorsoventral fig muscles. Mechanoreceptors: Mechanoreeeptors detect physical displacement of the body of body parts. Insects feed on crops and transmit plant diseases. 1. This mechanism move air into and out of the tracheal system. These legs stay on the ground at all times. Introduction to Phylum Onychophora: Onychophorans were previously grouped under arthropods, but recently they are considered to be a separate phylum that is closely related to the arthropods. (b) Tympanal (tympanic) organs: Tympanal organs are present in the legs of crickets and in the abdomen of grasshoppers and some moths and in the thorax of other insects. It is one of the successes of insect. The spiracles have closure device. Insects don't have spines; they are invertebrates. [better source needed], Molecular analysis suggests that the hexapods diverged from their sister group, the Anostraca (fairy shrimps), at around the start of the Silurian period 440 million years ago - coinciding with the appearance of vascular plants on land. It prevents the excessive water loss. 1. This, lens form one facet of the eye. A protective case encloses the pupal stage. All insects can respond to pressure waves with distributed setae. Login . The air pressure waves displace certain receptors. Some insects are capable of learning and remembering. 3. Maxillae: The maxillae have cutting surfaces. , "Fossil record of stem groups employed in evaluating the chronogram of insects (Arthropoda: Hexapoda)", "Hexapods - Hexapoda - Overview - Encyclopedia of Life", "Subphylum Hexapoda - Hexapods - BugGuide.Net", "Hexapoda facts, information, pictures | Encyclopedia.com articles about Hexapoda", "Hexapoda (Insecta): General Characteristics | easybiologyclass", "Class Hexapoda (Insects) (hexa, six + podus, feet) | Biology Boom", "The Metathoracic Pterygoda of the Hexapoda and Their Relation to the Wings", "Checklist of the Collembola: Are Collembola terrestrial Crustacea? Wings have thick hollow veins. Flies and wasps are examples of insects with an asynchronous flight mechanism. Hexapoda - The Insects : Classification. Thus they pick up caste- regulating pheromones from queen and pass it to other workers. Kumpulan 4 kamus bahasa Indonesia, termasuk KBBI, dan 6 kamus bahasa Inggris, mendukung pencarian multikata, frasa, akar kata, dll. These tasks are divided among workers according to age. Classification of Arthropoda: Classification Chart with Diagnostic / Identification Characters for Each Sub-phyla and Classes of Arthropoda by Easybiologyclass ... Ø Thorax with three pairs of jointed legs (hence the name hexapoda) ... Ø Segment 6 bears the labium which forms the lower lip of mouth Chemoreceptors: Insects use chemoreceptor in feeding, selection of egg sites mate location and for social organization. The thorax bears the wings as well as six legs in three pairs. 5. Honey bees have three of these castes in their colonies. Blood distributes nutrients, hormones and wastes and amoeboid cells. Intermediate concentrations causes molt to third immature stage. Hexapods have bodies ranging in length from 0.5 mm to over 300 mm which are divided into an anterior head, thorax, and posterior abdomen. It st initiates the formation of the new exoskeleton. This kind of development is called hemimetabolous metamorphosis. Low level of this hormone also causes the degeneration of the prothoracic gland. But it is actually a time of radical cellular change. Internal regulation takes place by interactions between endocrine glands and reproductive organs. Neurosecretory cells of the subesophageal ganglion synthesize ecdysiotropin. If you have previously obtained access with your personal account, Millipedes bear two pairs of legs per diplosegment, a feature that results from embryonic fusion of adjacent pairs of body segments, are usually rounder in cross-section, and are herbivores or detritivores. Grasshoppers and chinch bugs show paurco eiabolous metamorphosis. The annual value of insect-pollinated crops is 19 billion dollar per year in the United States. Flight is the most important form of insect locomotion. The new queens start killing each her, Only one queen remains. The characters of the wings are doubtless important as indications of relationship, but the nature of the jaws and the course of the life-history must be considered of greater value. It keeps their position stable.  In most insects the second and third thoracic segments also support wings. Their immatures are aquatic. For example. Hearing: Hearing is a mechanoreceptive sense. Arthropod - Arthropod - Classification: Modification, specialization, number, and appearance of body segments and appendages (especially anterior ones such as antennae and mouthparts) are important criteria in distinguishing arthropod classes.  It has been suggested that these may be homologous to the gill branches of crustaceans, or they may have developed from extensions of the segments themselves. Sperm receptacle is an out pocket of the female reproductive tract. They take the form of hairs, pegs, pits and plates. It causes orientation toward the pheromone source and stimulates an insect to attack or flight. Labium (lower lip)The mouth lies between the fourth and fifth segments and is covered by a projection from the sixth, called the labrum (upper lip). Hexapoda. Organisms Diversity … 2. They are mostly terrestrial. These interactions regulate the sexual maturity. Classification of Hexapoda: Sub-phylum Hexapoda is divided into two classes. The photoperiod indicates seasonal changes. It participates. class Hexapoda – insects; about five-sixths of all known species of animal. It is not replaced by carbon dioxide. Grasshoppers are jumping insects. (d) Cerci : Cerci are sensory structures. Sex pheromones: Sex pheromones excite or attract members of the opposite sex. Šesteronošci (Hexapoda), Potkoljeno Heksapoda (šesteronošci; grč. Bilateral placement of tympanal allows insects to differentiate between the direction and origin of sound. The head is composed of a presegmental acron that usually bears eyes (absent in Protura and Diplura), followed by six segments, all closely fused together, with the following appendages: The adult body size is attained. It is formed at the time of growth. Their eyes have evolved from the eyes of crustaceans, horseshoe crabs and trilobites. There is also some evidence suggesting that the hexapod groups may not share a common origin, and in particular that the Collembola belong elsewhere. Temperature. Soldiers: Soldiers are sterile. some zoologists use additional classification for insects, Their immature form is much different from t e adult form due to the presence of gills. For example: vedalia beetles are used for control of cotton-cushion scale. Any of numerous six-legged arthropods of the subphylum Hexapoda, which includes the insects and several groups formerly classified as insects, such as... Hexapod - definition of hexapod by The Free Dictionary ... any arthropod of the class Hexapoda (or Insecta); an insect. Most of these are innate (inherited). It covers a large air sac. There is a critical point midway into the down stroke. 2. Instar stores food for the transition to adulthood. (b) Wings: A pair of wings is attached at the dorsolateral margin of the mesothorax and metathorax. 1. These stimuli bring the male and female near each other. Classification and Attribute Selection Analysis for Hexapoda miRNA Binita Kumari1, Rati Sudha2, and Dr.A.K. They accelerate or retard sexual maturation. Excretory product: The excretion of uric acid has advantage for terrestrial animals. Chemoreceptors are abundant on the mouthparts, antennae, legs and ovipositors. Many insects provided valuable services and commercially valuable products. They transfer sperm to the queen.  As is typical of arthropods adapted to life on land, each leg has only a single walking branch composed of five segments, without the gill branches found in some other arthropods and with gill on the abdominal segments of some immature aquatic insects. Similar appendages are found on the heads of Myriapoda and Crustacea, although these have secondary antennae. The compound eye is used for detecting movement. Gutierrez (1981) [Statut pour Wallis et Futuna] Gutierrez, J. But energy is wasted in conversion of ammonia into uric acid. Theseglands are the corpora allata and the prothoracic glands. Large concentrations of juvenile hormone causes molt to second immature stage. The subphylum Hexapoda (from the Greek for six legs) constitutes the largest number of species of arthropods and includes the insects as well as three much smaller groups of wingless arthropods: Collembola, Protura, and Diplura (all of these were once considered insects). The resistance to wing movement suddenly decreases at the same time. Malpighian tubules and the rectum are primary excretory structures in the insects. Pauropoda. and heart. Invagination of respiratory surfaces takes place in insects. They are present on each segment. nida, Hexapoda (so-called "true insects"), Centipedes, and Millipedes. They can locate and recognize a potential mate for copulation. Respiration occurs through gills or general body … In this case a muscle does not move the wing directly. 1. All true insects have eleven segments (often reduced in number in many insect species), but in Protura there are twelve, and in Collembola only six (sometimes reduced to only four). Control of ecdysis by hormones: Ecdysis is under neuroendocrine control. The tracheal trunk is bra cited and rebranched and it gives rise to smaller branches called tracheoles. Sound waves in the frequency range of 500 to 550 cycles per second attract for mating behavior in male mosquitoes. The amount of juvenile hormone determines the nature of the next molt. It pulls the exoskeleton upward. The pupa appears inactive. Class – 1 : Insecta. Classification Order Neuroptera Subclass Pterygota Class Insecta Subphylum Hexapoda Phylum Arthropoda Kingdom Animalia; Size Range 5-150 mm; Introduction. It has a general excitatory influence on other body parts. Stretch receptors: Stretch receptors at the joints, on other parts of the cuticle, and on muscles monitor posture and position. The scale insect, lcerya purchasi, was introduced into California in the 1860s. The class hexapoda is divided in two subclasses: 1. Therefore, her behavior is innate. Ecdysiotropin hormone is then transferred to corpora cardiaca. Mandible: Mandibles are sclerotized chewing mouthparts. The classification of phylum arthropoda are as follows: Crustacea. Devonohexapodus bocksbergensis, a new marine hexapod from the Lower Devonian Hunsrück Slates, and the origin of Atelocerata and Hexapoda. The arthropods with three pairs of wing, one pair of antennae and three pairs of legs are called insects. They bear a sensory palp. Most other arthropods have more than three pairs of legs.. Fig: lnsect Flight (a) Muscle arrangements for the direct or synchronous flight mechanism. HEXAPODA (Gr. Workers lick and groom the queen and other workers. The blood vessels are less well developed in insects. For this reason, bees are attracted to flowers blowing in the wind. The final molt occurs within the cocoon, chrysalis, or puperium. Insects don't have spines; they are invertebrates. See more. Insects have many complex behavior patterns. The subphylum Uniramia is divided into three classes: Onychophora (velvet worms), Hexapoda (insects), and Myriapoda (‘pedes, both centi- and milli-). Brünnich, 1772 (To complete all classifications ETI has added the Kingdom and the Phyla of all the different taxa treated on this DVD-ROM without higher classification descriptions. Similarly, she has no experience to differentiate between the cell of queen and cells containing worker larvae and pupae. (c) Adult: The adult open the cocoon with its mandibles and come out. (b) Downward thrust: Then. It circulates the cooler air outside through the hive and cools their hive. the longitudinal muscles contract. It connects the gut, reproductive organs. Tracheoles are especially abundant in metabolically active tissues like flight muscles. Compound eye can detect the ultraviolet end of the spectrum. Pterygota (= winged and secondarily wingless insects)The subclass Pterygota is divided in two divisions: 1. However, other sources list Hexapoda as a subphylum rather than a class. The adult stage is associated with reproduction and dispersal. Phylum Porifera – Characteristics , Types , Functions & Reproduction, Answer of Question of Circulation Immunity & Gas Exchange. These muscles produce large propulsive forces. Insects have segmented bodies. L'Agronomie Tropicale, 5(11-12): 563-581. The head has antennae and a pair of compound eyes. Medical definition of Hexapoda: a class or other division of Arthropoda coextensive with the class Insecta. Therefore, the insects are as ectotherms. Your email address will not be published. Vector of the disease: Other insects transmit disease-causing microorganisms, nematodes and flatworms. (c) Spiracles: The thorax contains two pairs of spiracles. Their respiratory surface is composed of trachea. (b) Spiracles: Each abdominal segment has a pair of spiracles. These nerves enter into internal nerves. In true insects (class Insecta herein) the mouthparts are exposed or "ectognathous ", while in other groups they are enveloped or "endognathous ". Classification of Arthropods. The name Hexapoda describes the presence of six legs (three pairs) in these animals, which differentiates them from other groups of arthropods that have different numbers of legs. Thorax: The thorax consists of three segments. Fossils & Strata, No.45: 1-116 - copied from Nomina Circumscribentia Insectorum 5. Wind or water carry pheromones several kilometers away. 2. But the level of juvenile hormone increases again after the final molt. 4. The ommatidia are fused into a multifaceted eye. They explain it with the concepts of kin selection and altruism. It allows the stored energy to quickly ciond the legs.