This document discusses insect development and metamorphosis. It describes two types of development: incomplete and complete. Incomplete development involves nymphs that resemble wingless adults, while complete development involves distinct larval, pupal, and adult stages. The document outlines characteristics of orders that undergo complete metamorphosis, including Neuroptera, Lepidoptera, Hymenoptera, Diptera, and Coleoptera. It provides diagnostic traits for identifying immature stages of these orders.

1. Immature Insects Rick Story, Department of Entomology

3. Insect Growth - external skeleton -grows with successive molts -each stage is an instar -typically 5-7 instars for larval growth

4. Insect Metamorphosis - change in body form from immature to adult stage

14. Complete Metamorphosis -immatures do not look like adults -have an inactive pupal stage for transformation

19. Identification of Immatures Incomplete development orders – characters similar for nymphs and adults Complete development orders- characters completely different

20. Main orders with complete development Neuroptera : green + brown lacewings Lepidoptera : caterpillars (moths) Hymenoptera : sawfly larvae, ants, bees, wasps Diptera : maggots (flies) Coleoptera : white grubs, weevils, wireworms (beetles)

21. Neuroptera - Larvae are predators, with well developed legs and an elongated body -sickle shaped mandibles with blood groove diagnostic character

27. Lepidoptera - Larvae (caterpillars) are plant feeding and have chewing mouthparts -caterpillar body form diagnostic (cylindrical body, thoracic legs well developed, abdominal prolegs present)

36. Diptera - Larvae with variable feeding habits and chewing mouthparts -body with head capsule partially to completely reduced, no thoracic legs, soft bodied, white, often occur in damp habitats.

43. Coleoptera - Larvae with chewing mouthparts, plant feeding or predators -Have well developed head capsule, thoracic legs present (usually), and lack abdominal legs

54. Hymenoptera - sawflies: caterpillar body form (prolegs lack hooks), feed on foliage -bees, wasps, ants: grub-like body form with well developed head capsule and no thoracic legs.