Fundamentals of Entomology

TYPES OF LARVAE             Larva is the second immature stage of insects, which is the active stage. It is the stage between egg and pupal stages in insects with complete metamorphosis. Larvae totally differ from the adults. Types of larvae Larval type Description (Example) Protopod Resembles immature embryo, abdominal segmentation absent, thoracic and cephalic appendages rudimentary (Early instars of endoparasitic hymenoptera) Oligopod Thoracic legs only Campodeiform Body flattened with a typical prognathous head well developed thoracic legs (ladybird beetle, aphidlions and antlions) Scarabaeiform Stout semi cylindrical, C-shaped fleshy body, legs shorter (Coconut Rhinoceros beetle grub) Elateriform Flat, linear, long

TYPES OF INSECT EGGS             Egg is the first stage of development in all insects. The outer cover or the egg shell is called chorion. The chorion is lined within by vitelline membrane, which encloses the cytoplasm, yolk and nucleus. There is also a minute opening through which the sperm enters the egg for fertilization. Types of insect eggs             Insect eggs are much more variable in shape, structure, colour, possession of appendages and the way of laying as described below. Egg type Description Example Scaly Flat and scale like Coding moth Spherical Globular, mostly sculptured Swallowtail butterfly Oval Elliptical Japanese beetle Conical Cone like Cabbage worm Elongate Linear, rod shaped Leafhopper Barrel Cylindrical, erect Plant bugs Egg float Single