Introduction to Insect Anatomy

What Makes an Insect an Insect ???

Introduction

Because of the great diversity of form exhibited by the insects any introduction to anatomy like this is only going to be able to cover the basics, within each order and family these familiar themes are replayed in a myriad of different ways leaving what might seem to be a bewildering array of different body plans. A closer look will reveal the same basic plan in all insects, at least in the adult forms. Below are described some of the basic parts that make up an insects body.

An insect body has a hard exoskeleton protecting a soft interior, it is divided into three main parts ( the head, thorax and abdomen) each of which is in turn composed of several smaller segments.


 

Pete The Grasshopper

The Integument

 

The amazing success of the insects must in part lie with the incredible mixture of flexibility and strength of the integument (that is the part of an insect that makes up the hard exoskeleton) that allows the insects their freedom of movement without loss of defence and protection. It is made up of three parts, the most visible of which is the outer 'cuticle' and its attendant bristles and hairs, below this are the 'epidermis' and the 'basement membrane'

The Cuticle

 

The cuticle is a relatively thin layer of non-cellular material which lines the external surface of the body as well as lining the tracheae the anterior and posterior sections of the alimentary canal and parts of the reproductive system. It is flexible, elastic and white when first formed and stays this way in many larval forms, however in most adults it undergoes chemical processes which result in hardening and darkening and which are referred to as 'sclerotization'.

The cuticle can be divided into two layers, a very thin outer layer called the epicuticle which contains no chitin and is highly resistant to water and other solvents. Beneath this is the much thicker procuticle which can again be divided into two distinct layers, an outer 'exocuticle' which lies immediately below the 'epicuticle' and an inner 'endocuticle' which consists of a large number of layers of protein and chitin fibres laid down in a laminated pattern such that the individual strands in each layer cross each other thus creating an extremely tough and flexible substance.

Below the cuticle lie the other two components of the integument, the 'epidermis' which is a single layer of secretary cells and the 'basement membrane' which is an amorphous layer about 0.5 micrometres thick.

Jump Back to Pete the Grasshopper

 

The Head

 

The insect head is sometimes referred to as the head-capsule, and is the insects feeding and sensory centre, and supports the eyes, antennae and jaws of the insect. (Note -: insects do not breath through their mouths but through their thoracic and abdominal spiracles) The upper-mid portion is called the 'frons' below this is the 'clypeus' and below this the 'labrum' to either side of which may be seen the edges of the 'mandibles' in some insects various aspects of the 'maxilliary' palps may extend beyond and or below these even when viewed from front on.

The 'frons' = that area of the face below the top two 'ocelli' and above the 'frontoclypeal sulcus' (if and when this is visible) and in between the two 'frontogenal sulci', it supports the 'pharyngeal dilator' muscles and in immature forms it bears the lower two arms of the ecdysial cleavage lines.

The 'clypeus' = that are of the face immediately below the frons (with which it may be fused in the absence of the frontoclypeal sulcus) and the fc. sulcus. It supports the 'cibarial dilator' muscles and may be divided horizontally into a 'post.' and 'anteclypeus'.

The 'labrum' = is equivalent to the insects upper lip and is generally moveable, it articulates with the clypeus by means of the 'clypeolabral suture'.

The rest of the front of the head, that bit which is above the frons is known as the 'epicranium'.

Jump Back to Pete the Grasshopper

 

The Antennae

 

The antennae are primarily non-visual sense organs, though in some are instances they have become adapted for seizing prey items ( i.e. the larva of Chaoborus sp.) or holding females during mating (i.e. the males of Meloe sp.)
Not all insects possess antennae, they are absent from the Protura.
In most insects the antennae possess's a mechanosensory organ on the pedicel (the second antennal segment) called 'Johnston's organ'; Also only basal antennal segment contains intrinsic muscles, however in two orders (Diplura and Collembola) the antennae lack a 'Johnston's organ' and all but the last segment contains intrinsic muscles, thus allowing far greater controlled movement of the antennae as demonstrated in the rolling and unrolling of the antennae observed in the collembola Tomocerus longicornus
Antennae come in a wide variety of shapes and sizes, generally the first segment is known as the 'scape' the second segment as the 'pedicel' and the rest as the flagellum.

Jump Back to Pete the Grasshopper

The Eyes

 

Though some species of insects have been shown to be able respond to light stimulus through their cuticle, most light sensitivity occurs through one or more of a series of eyes. Insects possess two different sorts of eyes, the usually large and obviously visible compound eyes, and two varieties of ocelli or simple eyes.

Compound Eyes

 

Compound eyes are so named because the cornea is composed of a number of individual facets or lenses (called omatidia), rather than a single lens as in ocelli. The number of separate visual elements or omatidia varies greatly between species as well as between the larger taxa, so that while worker ants of different species may have between 100 and 600 omatidia per single eye, adult male Odonata may have more than 28 000 per single eye.

This creates a considerable difference in the presentation of light stimulus to the insect brain, however the ability of insects to navigate the world by means of visual stimuli suggest that they have overcome the problems inherent in this multi-faceted perception.

Simple Eyes

 

Ocelli are present in most insects to some degree, though as with all aspects of insect anatomy there is a great deal of variety in form and even in relative function. Generally they consist of five separate parts the 'cornea', the 'corneagen layer', the 'retina', the 'pigment cells', and the 'central nervous connections'.
1)The Cornea this is a thickened area of generally transparent cuticle to the outside of the ocellus which serves as a lens.
2)The Corneagen Layer this is a single layer of specialized transparent and colourless epidermal cells which secrete the cornea.
3)The Retina this is a group of primary sensory cells which convert light into an electrical stimulus and transfer it to the;
4)The Central Nervous Connections which link to the 'protocerebrum' and hence to the 'Corpora pedunculata' (the brain).
5)The Pigment Cells this is a group of highly pigmented (coloured) cells variably distributed around the ocellus whose main role would appear to be the exclusion of light from parts of the ocellus other than the cornea.

Two different forms of ocelli have been described for insects, Dorsal ocelli and Lateral ocelli.
Dorsal ocelli occur mostly in adult insects and are situated on the front of the insects face in the area of the 'frons' and or the 'epicranium', lateral ocelli generally occur on the sides of the insect head and are the form of eye most common in larval forms; there are a number of concrete differences between the two forms which can be be found explained in any competent entomological text book such as Imm's 1984.

Jump Back to Pete the Grasshopper

Hearing and other Senses

 

Ears

 

Many but not all insects can hear sounds, some even hear sounds that we can't hear ourselves. Insects hear through one of four different ways, the commonest of which is the tympanum. Tympanal organs always occur as paired organs, they are composed a thin cuticular membrane (the tympanum) stretched across an air space of some sort and some form of connection to the nervous system. In the Orthoptera (Grasshoppers and Crickets) tympanum are common, though situated in different places in different species, i.e. on the third thoracic segment in the Locusts Locusta migratoria and on the front legs in the House Cricket Acheta domesticus . Tympanal organs also occur in the Cicada (Cicadidae, Hemiptera) and some families of the Lepidoptera, (i.e.Noctuidae, Geometridae, and Pyralididae). The other three forms of hearing organs are 1) Johnston's Organ, via the movement of hairs on the antennal scape i.e. the Mosquito Aedes aegypti. 2) Auditory Hairs these occur on some Lepidopteran larvae as well as on some Orthoptera. 3) The Pilifer this is a unique auditory organ found only in the head of certain species of Hawk Moths of the subfamily Choerocampinae its optimum frequency is between 30 and 70 kHz.

Smell

 

Most insects communicate using smell or chemoreception and it is not surprising that they have evolved a large variety of ways of detecting the molecules involved. Insects do not have noses like us which concentrate all our sense of smell in one place, instead they have a lot of small sensory bodies scattered over their body, though they tend to have a concentration of them on their antennae. We can recognize several different common forms of chemoreceptor though these are not the only forms they can take by any means,
1) Sensilla trichoidea, hair-like structures commonly found on the feet of flies and the antennae of many insects, they are the commonest form of chemoreceptor found.
2) Sensilla basiconica and Sensilla styloconica, these are peg-like or cone-like and are thicker and more solid than trichoid sensilla, these are commonly found on the antennae, though they also occur on the maxillary palps of Lepidopteran larvae and the ovipositor of the Blowfly Phormia regina.
3) Sensilla coeloconica or pit-peg organs these are always situated in a pit as their common name suggests, unlike the previous two which project above the insects cuticle. They are common on a variety of insect antennae and and in Apis mellifera (the Honey Bee) they detect Carbon Dioxide.
4) Sensilla placodea these differ from the first three in that they consist of a flat plate of cuticle, they occur on the antennae of various Aphids and Apis mellifera (the Honey Bee).

Touch

 

Touch is an extremely important sense to insects and like smell insects have developed many different ways to detect mechanical stimulus, these all involve some form of physical change in the receptor, the commonest are hairs attached to nerves which react when the hairs are moved, these are called Trichoid sensilla. Another common type looks more like a drum with something pressing up against the skin of the drum from beneath, these are called Campaniform sensilla. Mechanoreceptors detect not only the physical interaction with another body but also air movements, changes in air pressure and also changes in the stresses being applied to the insects cuticle, thus allowing it to better control its movements and maintain balance.

Insects also use modified forms of the various sensory detectors described above to detect, changes in temperature, humidity and also in some cases to detect infra red radiations, x-ray radiation and the earths magnetic field.

Jump Back to Pete the Grasshopper

 

The Mouthparts

 

The insect mouth articulates (moves) from side to side in a horizontal plane, rather than vertically as do ours. It consists of a number of parts which, starting from the foremost, are called 1) The Labrum (as described above, the rest are described below), 2) The Mandibles, 3) The maxillae, 4) The Labium, 5) The Hypopharynx or tongue.

The Mandibles

 

The mandibles, with the maxillae, the labial palps and in some species the hypopharynx constitute the moveable aspects of the insect mouth, the mandibles and the maxillae are the equivalent of jaws with the exception that they move transversely (from side to side).
The mandibles show great variety within the insect orders and like our more familiar teeth they are hard and show variation in accordance with diet, thus they are sharp edged in carnivores, being extremely sickle like in the ant Aceton burchelli, whilst being adapted for crushing and chewing in herbivores. They have become a secondary sexual characteristic and are extremely large in some Beetles (i.e. in the genus Chiasognathus and Lucanus [Stag Beetles] ). In other orders they have become residual as in the adults of some Lepidoptera, or entirely absent as in the adults of the rest of the Lepidoptera, Trichoptera, Ephemeroptera and the Diptera.
Mandibles are are used not only for feeding but also for attack and defence, becoming extremely exaggerated in various species of termites ants (i.e. Atta texanus), and for manipulation of materials as in the nest building insects particularly the Hymenopteran Bees, Ants and Wasps.

The Maxillae

 

The maxillae are a pair of modified limbs which work behind the mandibles and in front of the labium as a pair of accessory jaws. They are composed of the following parts.
1) The Cardo, this is the piece nearest the head capsule and in some species of insect it is the only part of the maxillae that is connected to the head.
2) The Stypes this is central bulk of the maxillae and supports the;
3) Palpifer, which in turn supports the;
4) Maxilliary palp, which has one to seven segments and is mainly used as a sensory organ.
5) The Lacinia is situated at the distal end of the Stypes, is often serrated or toothed and serves to aid the eating process both by holding and masticating the food. It is boarded distally (to the far side in relation to the overall body) by;
6) The Galea and proximally (to the near-side in relationship to the body) by;
7) The Subgalea for more information on which I would recommend a specialist text on insect morphology (body shape) such as those by 'Snodgrass'.

The Labium

 

The labium results from the fusion of a pair of limbs and serves a purpose similar to our lower lip for the insects. The main body of the labium is divided into three parts the central 'mentum' which is boarded on either side by the 'submentum' proximally which hinges with the head, and the prementum distally. The prementum supports two pairs of lobes known as the 'glossae' and to the outside of them the 'paraglossae', and a pair of labial palps which are primarily sensory in function. The glossae and paraglossae may be fused, with one or the other considerably reduced, in which case the whole thing is known as the 'ligula'.

The hyper-pharynx or tongue is found behind the mouth, and has the salivary ducts at its base, in most Diptera (true flies) and Hemiptera (true bugs) it has become highly modified and serves as the main feeding organ, in many cases combining with the rest of the mouthparts to form a stylette or piercing organ.

Jump Back to Pete the Grasshopper

 

The Thorax

 

The thorax is the main engine room of the insect. It like the Abdomen is built up of a series of concave upper integumental plates known as 'tergites' and convex lower integumental plates known as 'sternites', the whole being held together by a tough yet stretchable membrane.
The thorax can be conveniently divided into three separate and normally easily visible sections called from the front, the 'prothorax' the 'mesothorax' and the 'metathorax'.
In the adult insects as well as in the nymphs of those insects with an 'incomplete metamorphosis' (those whose life cycle lacks the production of a pupa), each of these sections supports a pair of legs. In the pterygote (winged) insect orders the first two sections support a pair of wings, except in the Diptera (true flies) where the second or hind wings have become modified into a pair of club-like balancing organs called 'halteres'.

The Legs

 

The typical insect leg consists of six main sections;
1) The Coxa, this is the most basal aspect of the insect leg and articulates with the 'sternites'.
2) The Trochanter is usually small and serves as a joint between the 'coxa' and the 'femur'.
3)The Femur is usually long and stouter than the other segments and contains the main muscles used in running, jumping and digging.
4) The tibia is also generally long serving to increase the length of the leg, as well as adding an extra joint and thus extra flexibility the underside of the tarsal segments may possess pads.
5) The Tarsus is the foot of the insect leg and can consist of between one and five segments.
6) The Claws are situated at the end of the 'tarsus' and serve to assist the insect in holding onto the substrate or to its prey. Between the claws may be found a special pad known as an 'arolium' and which acts using suction developed by large numbers of minute tubular hairs to help hold the insect to smooth substrates.

Jump Back to Pete the Grasshopper

 

The Wings

 

Unlike legs, wings only occur in the adult forms of those insects which possess them, in those insects with 'incomplete metamorphosis' small wing buds are visible in the place the wings will occupy in the adult.
Generally speaking wings are thin flat structures consisting of two fine membranes supported by a series of sclerotized veins. In many small insects the veins may be absent and in some very small insects the wings consist of a central midrib supporting a series of fine hairs, these look more like feathers.
Wings are not totally stiff but bend and flex in an amazing manner during flight greatly improving their aerodynamics.
Most species of winged insect have two pairs of wings and in many of the more advanced orders these two wings are held together by a variety of mechanisms to form a single, larger, functionally wing.
Insect wings are soft and shapeless when the adults first emerge, but are immediately inflated with blood pressure through the veins before they are hardened and darkened by contact with the air.
Though most insect wings appear bare to the naked eye many are dotted with minute hairs and in some cases such as the 'Trichoptera' (Caddis Flies) completely clothed in fine hairs, or as in the 'Lepidoptera' (Moths and Butterflies) completely covered in tiny scales.
Though insect wings are primarily concerned with flight they serve a number of purposes, in the 'Coleoptera' (Beetles), and some 'Hemiptera' (True Bugs) the fore wings have become highly sclerotized and act as armour protecting the insect concerned. While some very small parasitic 'Hymenoptera' use their wings to swim through the water to their hosts.
The bright colours of many insect wings are there for mating purposes and allow males and females to recognize each other, in others the colours perform a role in camouflage hiding the insect from its predators, and in others they perform a thermodynamic role, the different colours reflecting and absorbing different wave lengths of light allowing the insect to control its internal temperature. In some insects the wings may perform two or more of these functions simultaneously.

Jump Back to Pete the Grasshopper

 

The Abdomen

 

The insect abdomen is built up of a series of concave upper integumental plates known as 'tergites' and convex lower integumental plates known as 'sternites', the whole being held together by a tough yet stretchable membrane. It contains the insects digestive tract and reproductive organs, it consists of eleven segments in most orders of insects though the 11th segment is absent in the adult of most the higher orders. In the 'Collembola' (Springtails) the abdomen has only six segments. Unlike other Arthropods the the insects possess no legs on the abdomen in the adult form, though the 'Protura' do have rudimentary leg-like appendages on the first three abdominal segments. Many larval insects particularly the 'Lepidoptera' and the 'Symphyta' (Sawflies) have appendages called 'pseudo' or prolegs on their posterior abdominal segments as well as their more familiar thoracic legs these allow them to grip onto the edges of plant leaves as they walk around.

Jump Back to Pete the Grasshopper

Inside the Insect

Breathing

 

Insects have no lungs! Most insects breath passively through their spiracles (special openings in the side of there cuticle) and the air reaches the body by means of a series of smaller and smaller pipes called 'Tracheae'. Diffusion of gases is effective over small distances but not over larger ones, this is one of the reasons insects are all relatively small. Insects which do not have spiracles and tracheae breath directly through their skins, also by diffusion of gases.

Jump Back to Pete the Grasshopper

 

The Muscles

 

Like us Insects need muscles in order to move the various different bits of their bodies around, however insects have their muscles are attached to the inside of their skeleton because like all the arthropods they have their skeletons on the outside of their body. The inside of an insects exoskeleton has special contours and bits and bobs on it which project inwards and allow for muscles to be attached and to help give them leverage, these projects are called 'apodemes'. The musculature of even the smallest insect can be as complicated as our own and makes for a fascinating study of design in miniature. The muscles of insects are generally light grey or translucent, unlike ours which appear red. This is because insects lack both the blood system that we have and the haemoglobin that makes our blood and hence our muscles red.

Jump Back to Pete the Grasshopper

The Heart and the Blood

 

The haemolymph (blood) of insects flows freely around the inside of their bodies. Because an insects haemolymph is not responsible for the transmission of oxygen to its cells (see Trachaea) and therefore does not contain haemoglobin, it is not red. Normally it is a watery green colour, though it is pigmented (coloured) in some species. This haemolymph is a sort of soup rich in nutrients that flows around the inside of the insects body allowing the various organs to get at whatever resources they need and into which they dump their waste products. These waste products are later removed from the haemolymph by the Malpighian tubules. Because insects do not have veins and arteries like us and the rest of the vertebrates, they do not need to, they do not have a complicated heart like ours either. The insect heart it is basically a tube, sealed at one end, which runs along their back. It beats thus swishing the blood in and out and around the body. You can get some idea how the heart of an insect works by cutting the nozzle off the top of an empty washing-up-liquid bottle and taking it into the bath with you. Hold it under the water and squeeze it a few times and watch how the water swirls around.

 

Jump Back to Pete the Grasshopper

 

Digestion

The Foregut

 

The Digestive system of an insect is usually a long straight tube running from the mouth to the anus, it is often divided into the 'foregut', the 'midgut' and the 'hindgut'. Immediately behind the mouth are the Salivary Glands, in most species these secrete saliva, generally a watery fluid that lubricates the food and contains a few enzymes to begin the processes of digestion. However in some carnivorous insects the saliva is composed entirely of digestive enzymes, this applies particularly to those with external digestion of the food. In other insects the salivary glands have become modified for purposes that have nothing to do with digestion. In Lepidopteran caterpillars and Caddisfly larvae they have been converted to the production of silk, while in the Queen Honey Bee they are called the mandibular glands and secrete hormones.

The foregut is generally considered to consist of four sections, the Pharynx, the Oesophagus, the Crop and the Proventriculus. It is also known as the Stomodaeum.

The pharynx is the first part of the foregut and apart from being a tube that connects the interior of the mouth area (sometimes known as the 'Buccal Cavity) with the more inwards parts of the gut it sometimes serves as a pump to suck up the liquefied food of those insects which feed by means external digestion. The Oesophagus is basically a tube leading to the midgut via the crop and the proventriculus. The crop is simply a stoage area and the proventriculus is a muscular extension of the crop in those insects which feed on solid foods. It is used to grind the food up into smaller particles, it can also serve as a filter to keep oversized particles out of the main digestive tract and a s valve controlling the flow of food into the midgut. The proventiculus is often referred to as the gizzard. The foregut and the midgut are separated by the 'stomodeal or cardiac valve'.

Jump Back to Pete the Grasshopper

 

The Midgut

 

The midgut (called the Mesenteron in some books) runs from the 'digestive or gastric caeca', a series of stubby pointed tubes leading of from the stomach (they are blue in Pete). To the Malpighian tubules, a series of long thin tubes (which are orange in Pete), in between these two is the stomach or ventriculus which is the area of most active digestion. The gastric caeca serve to increase the surface area of the midgut, thus increases both its ability to secrete digestive enzymes and its ability to extract useful products from the partially digested food. The useful proteins, vitamins and fats that are released by the digestive process pass across the wall of the midgut into the body cavity. The Malpighian tubules (named after Malpighi who discovered them) are not really to do with digestion at all but with elimination. They act like our kidneys and extract metabolic waste products (mostly nitrogenous ones such as urea, and uric acid) from the circulating body fluid called the haemolymph and excrete them into the intestines the first part of the hingut . The midgut is lined by a semipermeable membrane composed of protein and chitin like the cuticle which allows the passage of liquids and dissolved substances to the midgut wall while preventing the passage of solid food particles, it is continually worn away by the passage of food through the gut and replaced by the epithelial cells of the midgut wall. The midgut and the hindgut are separated by the 'proctodeal valve'.

Jump Back to Pete the Grasshopper

The Hindgut

 

From the midgut the food passes to the hindgut (called the Proctodaeum in some books). The hind gut comprises the 'intestines' where much of the difussion into the the insects body occurs. The 'rectum' which compresses the undigested food and waste products, extracts more water from this if necessry before it is passed out through the 'anus' as faeces.

Though insects possess a large number of digestive enzymes, they are often helped by the presence of symbiotic microorganisms, such as protozoa in the case of the termites and some primitive cockroaches which feed on wood, and bacteria in the wax moth Galleria mellonella which feeds on the wax that honey bees Apis mellifera uses to make the combs in its hives.

Jump Back to Pete the Grasshopper

Reproductive Structures

 

Most insect species are bisexual, i.e. there are males and females in most species, these often look very different and have even been mistaken for different species in the past, some species are capable of reproduction without males, the eggs are unfertilised but develop and hatch into nymphs or larvae that are always female themselves, this is called 'parthenogenesis'.

Externally the sexual organs, called genitalia, of a female insect generally consist of an 'ovipositor' which is often encased in a pair of filaments called a 'sheath' and is which is used to by the female to put her eggs where she wants. Its form very greatly throughout the Insecta (i.e. the whole order of insects). The ovipositor of the Diptera (True Flies) is functionally similar i.e. it is used to lay eggs, but is morphologically distinct i.e. it arises or is made from different parts of the insects anatomy and should be called a 'pseudovipositor'. The median part of the oviduct which receives the aedeagus during mating is called the 'vagina'

Externally the sexual organs of the male, also called genitalia, consist of a pair of 'claspers' which the male uses to hold onto the females genitalia and an intromittant organ called the 'aedeagus' which is the means by which the male passes the sperm onto the female.

Internally the female reproductive organs consist of a pair of ovaries which contain the ovarioles which is where the eggs or ova are formed, the bursa copulatrix which is where the sperm is first received )in those insects which have it) and a spermatheca which is where the sperm is stored. There are also various tubes down which the ova travels on its way from the ovaries to the outside world, fertilisation occurs in the common oviduct after the the egg has received its shell or the 'chorion'. To facilitate this the shell contains a very small opening at one end called the micropyle which allows the sperm to enter. As well as tubes there are several important glands some of which (spermathecal glands) allow the female to keep the sperm alive and viable for a long time, as much as 20 years in some social insects (Ants and Bees); and some of which (collaterial glands) secrete the substances which allow the female to stick the eggs where she wants then to stay i.e. underneath a leaf, or to protect the eggs as in the ootheca produced by the Cockroaches and Mantids

Internally the male reproductive organs consist of a pair of 'testes' containing the 'testicular follicles' where the spermatozoa are made, the 'vas deferens' which is the tube down which the sperm travels, a 'seminal vesicle' which is where the sperm is stored prior to mating, and accessory glands which supply seminal fluid for additional volume and to nourish the sperm before and during their journey.

Jump Back to Pete the Grasshopper

The Nervous System

 

The insect nervous system consists of a 'brain' (the result of 3 pairs 'ganglia' [a collection of neurons or nerve cells] fused together) and a pair of slender nerve cords called 'connectives' which run from it to the end of the insects abdomen, these are joined at intervals where a series of pairs of 'ganglia' (singular ='ganglion') occur the transverse fibres that connect the ganglia are called 'commissure'. There is usually one pair of ganglia per body segment, thus, as the head is made up out of 6 fused body segments it contains 6 pairs of ganglia, these are collected into 2 groups each of 3 ganglia the foremost of which is called the brain and the hindmost which is called the 'subesophageal ganglion'. The ganglia function to co-ordinate the activities of the body segment they represent, there are usually 3 thoracic ganglia and 8 abdominal ganglia but in some insects such as the Hemiptera (True Bugs) and some Diptera (True flies) the abdominal ganglia tend to fuse and have moved towards the most forward part of the abdomen.

Jump Back to Pete the Grasshopper


Pete the Prasshopper was originally drawn by my friend Debs Cooper specially for this site, any errors in the progamming or colour co-ordination though are entirely my responsibility. He is named after Dr. Peter Sutton the Devon recorder for Orthoptera and our mutual friend.


Back

By gordon@earthlife.net
 
  © Earth-Life Web Productions