8. What are the enemies of this insect? (Among the most important enemies of insects are birds, certain other insects, and various small vertebrates such as frogs, snakes, lizards, turtles, etc.) How does the insect protect itself from these enemies? 9. Describe the shell with respect to thickness and flexibility. What is the character of the surface as to roughness or smoothness or covering of hairs or scales? _Reproduction and Development._ _Note._--It may be necessary to get answers to these questions from books. 10. Where are the eggs deposited? What is the number of the eggs? How soon do they hatch? 11. What is the food of the larva or nymph? Are the food habits of the insects harmful to man? If so, how? 12. Describe the larva as to form, color, and appendages. Is it capable of locomotion? 13. Is the metamorphosis complete or incomplete? If complete, describe the pupa and tell where it may be found. _Drawings._ There should be one drawing of the insect to show its general characteristics; usually a dorsal view is best. For other drawings ask your instructor. 8. A REVIEW OF INSECTS _Directions._ The answers to questions in this study may be conveniently written in the form of a table. Construct this table by placing the topics at the left and the names of insects at the top. Allow ample space, about one half inch for the horizontal spaces and one and one half inches in width for the vertical columns. Use one or two insects from each of the principal orders, letting the table extend across two opposite pages. _Topics._ 1. What is the habitat? 2. What regions has the body? 3. How many antennæ? What is their form? 4. What kinds of eyes has the insect? How many of each kind? 5. How many legs? 6. For what kind of locomotion are the legs adapted? Which legs are thus used? 7. How many wings? Membranous or thickened? 8. What is the position of the wings when at rest? 9. If the fore wings are thickened, what is their texture,--leathery, smooth and sheath-like, partly membranous, covered with scales? 10. What kind of mouth parts,--jaws for biting, a beak for piercing, a tube for sucking, adapted for both sucking and biting? 11. By what means is respiration accomplished? Summary of Important Points from the Table 1. What characters are common to all the insects described in the table? 2. What are the various types of wings? Why do they vary? 3. What are the various types of legs? How are they characterized? 4. What are the various types of mouth parts? 5. Show how the variations in insects are related to the habitat and mode of life of the insect. 9. KEY TO THE PRINCIPAL ORDERS OF INSECTS A^1 Insects with _no_ wings. (See list below.) A^2 Insects with wings B B^1 With _two_ pairs of wings. (See Note 1 below.) C B^2 With _one_ pair of wings Diptera