Biology-Mr.Willets
Lab-Grasshopper
The grasshopper is a member of Phylum Arthropoda, Class Insecta, Order Orthoptera. The genus name for your specimen is Romalea. Use the large chart and the books (pg 441)to help identify the parts in boldface print.
EXTERNAL ANATOMY-
Examine your specimen. Notice there are three main body sections- the head, thorax and abdomen. The thorax is made of 3 segments and the abdomen has 11 segments. Where the head and the thorax meet is hinged so that the head can move separately from the thorax. Compare this (in your mind) to the cephalothorax in the crayfish.
There are two compound eyes. Examine these with the hand lens. Look for the individual lenses. Just above each compound eye is a simple eye. There is a third simple eye in the middle of the head. Use the hand lens to look for these. There is one pair of antenna. These may be missing in your specimen.
As in all insects, there are 3 pairs of legs. The grasshopper has 2 pair for walking and one pair for jumping. The jumping legs are not found in most insects. In some of our specimens, the jumping legs may be damaged.
There are 2 pairs of wings. The anterior wings or forewings are heavy and cover the more delicate hindwings. Open the wings and see the difference. In beetles, the forewings have become more of a protective cover than wings. These give a beetle its distinctive look.
Partially hidden by the legs, on each side of the first abdominal segment, is a tympanum or eardrum. It is oval shaped.
Insects breath through a complex system of tubes called trachea. These bring oxygen directly to all body parts. There are openings to these tubes along the side of the insect. These openings are called spiracles. Use the hand lens to look for these. Since the blood is not used to carry oxygen to the muscles, the insect can have open circulation and still be fast moving.
If your specimen is a female, the tip of the abdomen is used to lay eggs. It is called an ovipositor (ovi=egg , positor = depositor). Worker bees, which are sterile females and therefore do not lay eggs, have a modified ovipositor which is their stinger.