_Femur_, _tibia_, and _tarsus_, the three principal divisions of the leg corresponding to thigh, shank, and foot. _Veins_, thread-like thickenings of the wings. _Ocelli_, the single or simple eyes of an insect, composed of a single eye element. _Compound eyes_, made up of many eye elements. _Auditory sacs_, organs for hearing in many animals. _Antennæ_, the feelers borne on the head. _Labrum_, the upper lip. _Labium_, the lower lip, formed by the growing together of the second maxillæ. _Mandibles_, primary jaws situated under the labrum. _Maxillæ_, secondary jaws just in front of the labium, each composed of three parts, a palp, a spoon, and a tooth. _Palps_, the jointed finger-like structures used to handle food, one pair on the labium and one pair on the maxillæ. _Spiracles_, openings into the trachea found along the sides of the abdomen and thorax. _Tracheæ_, slender tubes used for breathing organs among insects. They carry the air direct to the tissues in all parts of the body. _Ovipositors_, structures on the posterior end of the abdomen of a female, used to deposit eggs. _Metamorphosis_, refers to the development of the young of animals when striking changes in structure occur in the course of their growth. Metamorphosis is called _complete_ when the young have no resemblance to the adults, and _incomplete_ when there is a resemblance to the adult. In complete metamorphosis the stages are _larva_, _pupa_, and _adult_. In incomplete metamorphosis the stages are _nymph_ and _adult_. _Observations._ _The Body._ 1. Show how the shape of the grasshopper's body is well adapted to its needs. 2. Which region of the body is the thickest? What seems to be the reason for this? Which regions are capable of movement? _Locomotion._ 3. What are the various kinds of locomotion a grasshopper can use? Which are used in the vivarium and which when free in the laboratory? 4. Which legs are used in jumping? How are these legs especially adapted to this, in length, structure and direction? Could a grasshopper jump if the third pair of legs were arranged like the other two pairs? Why? 5. How is the animal able to cling to grass stems and not slip down? What is the direction of the body in relation to the stem or grass blade? 6. What is the position of the wings when at rest? when in use? How do the hind wings fold? How are the principal veins of the wings arranged to permit or facilitate this folding? 7. Contrast the fore and hind wings with respect to thickness, size, and use. 8. To which somites of the thorax are the wings attached? Nearer which surface, the dorsal or ventral? Why? _Sense Organs._ 9. Discover all you can about the uses of the antennæ by carefully observing grasshoppers at rest, feeding, jumping and crawling, approaching an object or another grasshopper, etc. 10. How many compound eyes has the grasshopper? How many simple eyes? Where are they located?