The types here given are only a few of the many to be found in the early fall, and these exercises in several cases may be used for other forms than those definitely mentioned. There should be a great deal of promiscuous collecting by the class, and in the mass of material gathered the following types will probably be fairly abundant. THE LIVING FLY _Materials._ Living flies in cages and individual specimens in small wide-mouth vials with cotton stoppers for the admission of air. Sugar crystals may be used for feeding. Simple lenses. _Observations._ Notice the division of the body into three regions: head, thorax, and abdomen. The six legs, the large wings, and the small feelers may be easily found, as are the large eyes, the extensible mouth, and beneath the larger wings the small undeveloped ones looking like tiny knobs. 1. State the general color of your specimen and give any special markings on its body. 2. Is the body smooth or has it a covering of any kind? Do you regard the fly as a cleanly animal? Why? 3. Under what conditions does the fly use its legs? its wings? What enables it to walk upside down? What use can you assign to the small wings? 4. Judging by the relative size of the feelers and the eyes, do you think the fly relies more upon its sight or its feeling? Since the eyes can probably see you any place where you see them, determine through how much of a circle the fly can see. 5. How does the fly eat? Does it eat solid or liquid food? 6. Where is the extensible mouth (_proboscis_) kept when not in use? What is the fly doing when "washing its face"? 7. From your own observation in the barn and the alley what do you know about the fly's cleanliness in choosing its food? How would it affect articles in the pantry? 8. From the foregoing statements show how flies may be a serious factor in dealing with disease. 9. What means may be employed as protection against adult flies? against their breeding places and "maggots"? _Suggested drawing._ a. The entire fly, seen from above, × 4. THE LIVING MAGGOT _Materials._ Living specimens in pans or cotton-stoppered bottles, with some food material and moist cloth or paper; lenses. _Observations._ Notice the general worm-like form of the maggot, or grub, the plain and uniform color, and the absence of all elaborate structures, as wings and feelers. 1. Since this creature is destined to become a flying or walking insect, what organs will have to appear? Is there any indication of these structures at present? 2. Give the color of the specimen, and explain how the presence or absence of strong light seems to have affected the color. Is this effect usual in animals or plants that you know? 3. Tell how the animal gets from place to place, describing any special structures you find which aid in this work.