1. They are triploblastic organisms, bilaterally symmetrical and segmented.
2. The body is divided into tagmata. The body is divided into head, thorax and abdomen.
3. They are animals with jointed appendages. The head has a pair of antennae and a pair of antennae.
4. The appendages of the body are changed to form the mouth. It takes food.
5. The exoskeleton is made up of cuticles and regularly sheds or molts.
6. The body cavity is known as hemocele. It is filled with blood.
7. Their main excretory organ is the Malpighian duct. But excretion is also done by green gland, chyloe, coxal gland, antennal gland and maxillary gland.
8. The circulatory system is open type. It consists of the heart, arteries and hemocele.
9. Respiration is accomplished through their trachea, gills, skin, gills, or pectoral fins.
10. Men and women are separate animals. Their internal fertilization occurs. Turns into an explosion.
11. The life cycle consists of larva, pupa and nymph stage.
12. They live as terrestrial, aquatic, sessile, free-living, parasitic or symbiotic.
[Key words to remember features: triploblastic, tagmata, pujakshi, moulting, hemocele, malpighian duct, chest lung]