What is the shape of the lady bug (Fig. 97)? It feeds upon plant lice (Fig. 185). Is any beetle of benefit to man? [Illustration: FIG. 170.—Life history of ant lion. ] =Illustrated Study of Ant Lion, or Doodle Bug= (Fig. 170).—Find the pitfall (what shape?); the larva (describe it); the pupa case (ball covered with web and sand); the imago. Compare imago with dragon fly (Fig. 177). How does ant lion prevent ant from climbing out of pitfall (see Fig. 170)? What is on edge of nearest pitfall? Explain. Ant lions may be kept in a box half filled with sand and fed on ants. How is the pitfall dug? What part of ant is eaten? How is unused food removed? How long is it in the larval state? Pupal state? Keep net over box to prevent adult from flying away when it emerges. [Illustration: FIG. 171. ] [Illustration: FIG. 172.—Metamorphosis of house fly (enlarged). ] [Illustration: FIG. 173.—Metamorphosis of flea. ] [Illustration: FIG. 174.—Louse and its eggs attached to a hair. Natural size and magnified. ] [Illustration: FIG. 175.—Bed bug. × 5. ] [Illustration: FIG. 176.—Life history of mosquito. ] =Illustrated Study of Insect Pests= (Figs. 171–176).—Why does the _clothes moth_ (171) lay its eggs upon woollen clothing? How does the larva conceal itself? The larva can cut through paper and cotton, yet sealing clothes in bags of paper or cotton protects them. Explain. The _house fly_ eats liquid sweets. It lays its eggs in horse dung. Describe its larval and pupal forms. Banishing horses from city would have what beneficial effect? Describe the _louse_ and its eggs, which are shown attached to a hair, natural size and enlarged. Describe the _bed bug_. Benzine poured in cracks kills bed bugs. Do bed bugs bite or suck? Why are they wingless? Describe the larva, _f_, pupa, _g_, and the adult _flea_, all shown enlarged. Its mandibles, _b_, _b_, are used for piercing. To kill fleas lather dog or cat completely and let lather remain on five minutes before washing. Eggs are laid and first stages passed in the ground. How does the _mosquito_ lay its eggs in the water without drowning (176)? Why are the eggs always laid in still water? Which part of the larva (wiggletail) is held to the surface in breathing? What part of the pupa (called tumbler, or bull head) is held to the surface in breathing? Give differences in larva and pupa. Where does pupa change to perfect insect? Describe mouth parts of male mosquito (at left) and female (at right). Only female mosquitoes suck blood. Males suck juice of plants. Malarial mosquito alights with hind end of body raised at an angle. Why does killing fish and frogs increase mosquitoes? 1 oz. of kerosene for 15 ft. of surface of water, renewed monthly, prevents mosquitoes. What is the use to the squash bug (Fig. 184) of having so bad an odour? [Illustration: