Class 4. INSECTA. Tracheata with the body divided into three regions : (i) the head with a single pair of antennae 

 and mouth parts, (i) the thorax with three pairs of legs and usually two pairs of wings, and (3) the 

 abdomen with 10 segments usually without appendages. Young always more or less different from adult. 



Order r. COLLEMBOLA. Spring-tails. "| Wingless insects whose ancestors are believed to have been also 



Order i. THYSANURA. Bristle-tails. J wingless. 



Order 3. SIPHON APTERA. Fleas. Wingless animals supposed to have developed from winged ancestors. 



Order 4. ORTHOPTERA. Earwigs, locusts, crickets, grasshoppers, leaf- and stick-insects. 



Order 5. ISOPTERA. (Termitidse) white-ants. 



Order 6. PARANEUROPTERA. (Odonata) dragon-flies. 



Order 7. HEMIPTERA. Bugs, plant-lice. 



Order 8. NEUROPTERA. Ant-lions, lace-wings. 



Order 9. LEPIDOPTERA. Moths and butterflies. 



Order 10. COLEOPTERA. Beetles. 



Order u. DIPTERA. Flies. 



Order 12. HYMENOPTERA. Ants, saw-flies, bees, wasps. 



