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Phone : 01425-254022, (O) 01425-254022 (Fax) Dr. G.L. Keshwa February 22, 2010 I am really glad to know that the Practical Mannual for Insect Morphology and Systematic has been prepared for B.S.c. Ag. Hons. Part-I students by Dr. M.C. Bhargava and Dr. Ashok Sharma, Department of Entomology. The practical manual will fulfill the need and necessity of Introductory Entomology and will provide the guidelines for the students. I congratulate the authors in bringing out this publication and wish them all the success in their future eneavour. PREFECE The main aim of preparing this practical manual is to provide the undergraduate students of Agriculture, a simple exposition of the subject. It is primarily designed to cover the syllabus of Insect Morphology and Systematics (Ento- 4121). The manual contains details about introductory entomology including external and internal anatomy of grasshopper and classification of orders of agriculture importance up to family level. We feel immense pleasure in expressing our heartfelt regards with deep sense of gratitude to Dr. G L Keshwa, Dean, SKN College of Agriculture, Jobner for giving inspiration to prepare this manual. Place Jobner M.C. Bhargava Date ........................ Ashok Sharma Ento 4121 INSECT MORPHOLOGY AND SYSTEMATICS 3(2+1) CONTENTS S. No. Exercise Date Remark 1. Observing and sketching of external structure of grasshopper .................... ........................ 2. Acquaintance with the insect collection material .................... ........................ 3. Pinning of different type of insects and .................... ........................ preservation of different stages of insects 4. Preparation of temporary mount of biting and .................... ........................ chewing type of mouth parts. 5. Preparation of temporary mount of sponging and .................... ........................ chewing and lapping type of mouthparts 6. Preparation of temporary mount of piercing and .................... ........................ sucking type of mouthparts 7. Mounting of different types of antennae .................... ........................ 8. Mounting of different types of legs .................... ........................ 9. Observing different types of wings, modification .................... ........................ and wing coupling apparatus 10. Dissection of grasshopper/cockroach to expose .................... ........................ digestive and nervous system 11. Dissection of grasshopper/cockroach to expose .................... ........................ reproductive organ. 12. Observing the characters of order Orthoptera and .................... ........................ Isoptera and its families of Agriculture importance 13. Observing the characters of order Lepidoptera .................... ........................ and Thysanoptera and its families of Agriculture importance 14. Hymenoptera and its families of Agriculture .................... ........................ importance 15. Observing the characters of order Coleoptera .................... ........................ and its families of Agriculture importance 16. Observing the characters of order Diptera and .................... ........................ its families of Agriculture importance Exercise No. - 1 OBSERVING AND SKETCHING OF EXTERNAL STRUCTURE OF GRASSHOPPER The super class Hexapod has three distinct body divisions viz., head, thorax and abdomens, normally with a pair of antennae, a pair of compound eyes, a pair of mandibles, two pairs of wings and abdomen with no locomotory appendages. They are tracheal arthropods. Body covered with a chitinous exoskeleton. 1. Head Depending on the orientation of the head, insect head are categorized in to three types viz., Prognathous, Hypognathous and opisthognathous. In grasshopper the head is hypognathus since the mouthparts are at right angle to body axis. Sutures and area of head 1. Frons: Is is an area on the anterior face lies below the vertex and extent from frontal suture to clypeus and up to the base of both the mandibles. 2. Clypeus: It is a lip like area frontal suture, which lies above frons. The ocelli and antennae are situated in this region. 3. Vertex: The part above the frontal suture, which lies above frons. The ocelli and antennae are situated in this region. 4. Epicranial suture: The inverted „Y‟ shape structure lies between the eyes. 5. Genae: Lateral walls of the head situated below the eyes. 6. Post genae: The area directly posterior to the eyes. 7. Commound eyes: Paired structure situated dorsoventrally. 8. Ocelli: Located between the compound eyes generally three in number. 9. Tentorium: The endoskeleton of the head. 10. Ocular sclerite: compound eye is surrounded by a narrow ring like structure known as ocular sclerite. 11. Occiput: Hinder part of the head region. Appendages of head Antennae: The paired segmented sensory organs are born one on either side of the head. A typical antenna consists of three regions, the scape, the pedicle and the flagellum. Mouthparts: Typically insect mouthparts consist of the labrum or upper lip, the labium or the lower lip, a pair of mandibles or the upper pair of jaws, a pair of maxillae or the lower pair of jaws and a median fleshy tongue like roof. In grasshopper the mouthparts are of the mandibulate or biting and chewing type. Labrum: The labrum is a flap like structure attached to the clypeus bearing many sensilla and is known as „epipharynx‟. Mandibles: A pair of maxillae is located behind the labrum adapted for cutting or crushing the food. It is movable by mean of two powerful muscles, the adductor and adductor muscles. Maxillae: A pair of maxillae is located behind the mandibles. The maxillae are used for holding the foods. Each maxilla composed of following segments. (a) Cardo: Triangular, basal part. (b) Stipes: Rectangular, central part. (c) Galea: It is the outer lobe. (d) Lacinia: It is the inner lobe. (e) Maxillary palp: Antennae like appendages attached with the both sides of the stipes. Labium : The unpaired labium consists of two plates, the mentum and prementum. The post mentum is divided into sub mentum and mentum, connected to the prementum. Two pairs of lobes, the glossa and paraglossa and a pair of lateral labial palpi with up to three segments are attached to the pre mentum. Hypopharynx: It is a tongue like structure arising from the floor of the mouth cavity. The salivary glands open through it. 2. Thorax It is the second of the insect body bearing three pairs of legs and two pairs of wings, when present. It consists of three segments, the prothorax, the mesothorax and the metathorax. The flexible inter segment region between the head and prothorax is known as the cervix or the neck region. Each thoracic segment of an insect is typically made up of four sides, the dorsal notum, the ventral sternum and the two lateral pleura. Thoracic appendages Legs: Each of the thoracic segment bears a pair of legs located on the ventral surface. Typically each leg consists of six parts, coxa, trochanter, femur, tibia, tarsus and pretarsus. Wings: Typically, adult insect have two pairs of wings. However, there may be reduction in the number of wing to one pair as in Diptera. Primitive insects lack wings. Insect‟s wings are broadly triangular and three sides and three angles could be seen. Three margins: Anterior margin (costal margin), outer or the apical margin and the inner or anal margin. Three angles: Humeral angle, apex angle and anal angle. 3. Abdomen Posterior region of the insect body typically consists of 10-11 segments, but the number varies in different insects. In grasshopper 11 segments are present. In both the sexes a pair of podical plates and a pair of cerci present. In males a pair of style are present along with the cerci. Anal opening is present on the 10th segment. The genitalia opening are ventrally on the 8th in female and between 8th and 9th segments in male. Exercise No. -2 ACQUAINTANCE WITH THE INSECT COLLECTION MATERIAL The equipments required for collecting insects includes; insect net, killing bottle, collection box, vials for preservation, forceps, aspirator, knife for open galls and bark and insect pins. Insect net An insect net consists of a handled fitted with a wire ring to which a cloth bag is attached. The aerial net is used to collecting insects such as butterflies, dragonflies and wasps, It should be light in weight and provided with mosquito netting bag. The length of the bag should be about twice the diameter of the ring. Care and use Flowers and other parts should be swept with a side vise motion. This will collect more insects then upward and downward sweep. Short stroke are more effective than long stroke. Killing bottle When an insect has been collected, it should be killed as quickly as possible in a killing bottle to avoid damaging the specimen. Any wide mouth bottle be used for preparing a killing bottle. How to prepare a killing bottle Several chemicals are available for use killing agent in the bottle. Ethyl acetate and cyanide are the most satisfactory. Chloroform and carbon tetrachloride may be used as substitute killing agent when the other compounds are not available. The best killing bottle is made by potassium cyanide, sodium cyanide and calcium cyanide. These compounds give a concentration of deadly fumes sufficient to kill most insects in short time. The bottle is charged by filling a small lump of potassium cyanide and then filling the chinks between the lumps with dry plaster of paris is now made up with a minimum of water