1. Observations on external features of grasshopepr cockroach.pptx

Prominent on the outside of the capsule are a pair of antennae, two large compound eyes, and the downward directed mouthparts. The antennae of grasshoppers are usually filiform (threadlike) but they may have other shapes, such as ensiform (broad at base, narrowing to tip or clavate (expanded at tip)

1. Ex.No:1. Observations on external features of grasshopper / cockroach Dr. L. RAMAEAME Ph.D Assistant Professor Agricultural Entomology CAS-SRMIST

2. External structures of Grasshopper 1. Head 2. Thorax 3. Abdomen Head Most anterior and compacted body division Segmentation is not clear, strongly sclerotized Head is composed of A Pair of antennae A pair of compound eyes 3 dorsal ocelli Mouth parts Cranium : the sclerotized capsule – appendages Head capsule is covered with hardened plates or sclerites Sutures : soft parts or joints between sclerites

3. Compound eyes Are dorsolateral position Located on either side of head Each eye consist of a no. of individual sensory units called – ommatidia Externally these ommatidia are marked by hexagonal cuticular structure called – facets Fun: c.eyes major photoreceptors-useful for image perception

4. In between c.eyes are situated 3 – simple eyes or dorsal ocelli Out of 3 – one is median in position other 2 are placed above on each side Each simple – has a single lens Fun: they are useful to sensitive to light but not useful in image perception.

5. Antenna They are paired segmented appendages Articulate with the cranium b/w the C. eyes segments are uniform thickness – e.g : Thread like ( Filiform ) Fun: flexible and sensory in function

6. Mouth parts Are mandibulate –suited for biting and chewing the food M.p : consist of 2 lips- labrum labium 2 pairs of jaws- mandibles maxillae a tongue like organ – hypopharynx

7. Head Connected to thorax by a membranous region called : Neck or Cervix Cervical membrane function Highly flexible Allows movement of head Main function of head Feeding and sensory perception

8. Thorax Middle body region Heavily musculated Three segmented 1. Prothorax 2. Mesothorax 3.Metathorax Each thoracic segment consist of a 1.Dorsal sclerites – Notum or Tergum 2.Lateral sclerites – Pleuron – membranous 3.Ventral sclerites –Sternum

9. Notum of Prothorax is called –pronotum 2 pairs of respiratory opening – Spiracles or Stigmata –located on lateral side of meso and Metathorax Each thorax bears a pair of segmented legs

10. Leg Each leg consists of 5 segments Coxa Trochanter Femur Tibia Tarsus Tarsus ends with Pretarsus

11. Pretarsus consists of – a pair of claws , median lobe – Arolium Fore and middle legs are suited for walking Hind leg –suited for jumping

12. Wings The wing bearing thoracic segements - meso and metathorax Meso and metathorax collectively called pterothorax Mesothoracic wing is called – Forewing F.w - leathery are known as – Tegmina Metathoracic wing is called – Hindwing Larger and membranous Fun. Of thorax :concerned for locomotion

13. Abdomen Posterior tagma Longest of the three body region Rather Soft compared to the rest of the body Segmentation is more evident in abdomen Consists of 11 telescopic segments Segments are joined by intersegemental membrane – conjunctiva Which make the abdomen more flexible –used for copulation and oviposition

14. Each abdominal segment made up of two sclerites Dorsal plate -Tergum Ventral plates-Sternum Here there is no pleuron An oval shaped transparent auditory membrane- Tympanum Tympanum – found laterally on either side of 1 st abdominal segment 8 pairs of abdominal spiracles. 1 st pair present on the 1 st abdominal segment Remaining 7 pairs are found on the either side of the tergum

15. Posterior abdominal segments are used for mating and oviposition Genitalia – male external sexual organs present on 9 abdominal sternum Genitalia consists of median intromittent organ –Aedeagus lateral clasping organs- parameres Ovipositer - female egg laying apparatus Present on 8 and 9 abdoinal sternum

16. Ovipositor 2 pairs of basal sclerites- valvifers 3 pairs of elongated processes –valvulae Doral and ventral valvulae –short, hooked and highly sclerotized –useful to dig the soil Medial valvulae –small- act as egg guide Dorsal Inner or ventral Median valvulae

17. On the 11 th segment –triangular dorsal plate called – Epiproct Paired lateral plates – paraprocts b/w epiprocts and paraprocts -there is short unsegmented cerci Fun: sensory in function