Fig. 139.—May Fly. What order (see table)?
Fig. 140.—Silver Scale. (Order?)
Exercise in the Use of the Table or Key.—Write the name of the order after each of the following names of insects:—
Moths and Butterflies.—Order ____? Why ____ (p. 82)?
The presence of scales on the wings is a never-failing test of a moth or butterfly. The wings do not fold at all. They are so large and the legs so weak and delicate that the butterfly keeps its balance with difficulty when walking.
The maxillæ are developed to form the long sucking proboscis. How do they fit together to form a tube? (See Fig. 147.) The proboscis varies from a fraction of an inch in the “miller” to five inches in some tropical moths, which use it to extract nectar from long tubular flowers. When not in use, it is held coiled like a watch spring under the head (Fig. 148). The upper lip (labrum), under lip (labium), and lip fingers (labial palpi) are very small, and the mandibles small or wanting (Fig. 146).
The metamorphosis is complete, the contrast between the caterpillar or larva of the moth and butterfly and the adult form being very great. The caterpillar has the three pairs of jointed legs typical of insects; these are found near the head (Fig. 141). It has also from three to five pairs of fleshy unjointed proplegs, one pair of which is always on the last segment. How many pairs of proplegs has the silkworm caterpillar? (Fig. 143.) The measuring worm, or looper? (Fig. 136.) The pupa has a thin shell. Can you see external signs of the antennæ, wings, and legs in this stage? (Fig. 143.) The pupa is concealed by protective coloration, and is sometimes inclosed in a silken cocoon which was spun by the caterpillar before the last molt. Hairy caterpillars usually produce butterflies, and the naked ones usually produce moths. Hairy ones are uncomfortable for birds to eat. The naked and brightly marked ones (warning coloration) often contain an acrid and distasteful fluid. The injuries from lepidoptera are done in the caterpillar stage. The codling moth (Fig. 141) destroys apples to the value of $6,000,000 annually. The clothes moth (Fig. 171) is a household pest. The tent caterpillar denudes trees of their leaves. The only useful caterpillar is the silkworm (Fig. 143). In Italy and Japan many of the country dwellings have silk rooms where thousands of these caterpillars are fed and tended by women and children. Why is the cabbage butterfly so called? Why can it not eat cabbage? Why does sealing clothes in a paper bag prevent the ravages of the clothes moth?
Flight of Lepidoptera.—Which appears to use more exertion to keep afloat, a bird or a butterfly? Explain why. Of all flying insects which would more probably be found highest up mountains? How does the butterfly suddenly change direction of flight? Does it usually fly in a straight or zigzag course? Advantage of this? Why is zigzag flight unnecessary to moths? Bright colors are protective, as lepidoptera are in greatest danger when at rest on flowers. Are the brightest colors on upper or under side of wings of butterfly? Why? (Think of the colors in a flower.) Why is it better for moths to hold their wings flat out when at rest? Where are moths during the day? How can you test whether the color of the wings is given by the scales?
State how moths and butterflies differ in respect to: body, wings, feelers, habits; abundance of scales.
Insects and Flowers.—We are indebted to insects for the bright colors and sweet honey of flowers. Flowers need insects to carry their pollen to other flowers, as cross-fertilization produces the best seeds. The insects need the nectar of the flowers for food, and the bright colors and sweet odors are the advertisements of the flowers to attract insects. There were no flowers in the world before flying insects were developed. Moths, butterflies, and bees carry most pollen (see Plant Biology, Chap. VI).
Comparative Study.—Make a table like this, occupying entire page of notebook, leaving no margins, and fill in accurately:—
| Grass- hopper |
Butter- fly |
Fly pp. 92, 93 |
Dragon Fly, p. 93 |
Beetle pp. 90, 91 |
Bee pp. 88, 89 |
|
|---|---|---|---|---|---|---|
| Number and kind of wings | ||||||
| Description of legs | ||||||
| Antennæ (length, shape, joints) | ||||||
| Biting or sucking mouth parts | ||||||
| Complete or incomplete metamorphosis |
Fig. 141.—Codling Moth, from egg to adult. (See Farmers’ Bulletin, p. 95.)
Fig. 142.—Cabbage Butterfly, male and female, larva and pupa.
Fig. 143.—Life History of Silkworm.
Fig. 144.—Scales from Butterflies’ Wings, as seen under microscope.
To the Teacher: These illustrated studies require slower and more careful study than the text. One, or at most two, studies will suffice for a lesson. The questions can be answered by studying the figures. Weak observers will often fail and they should not be told, but should try again until they succeed.
Fig. 145.—Scales on Moth’s Wing.
Fig. 146.—Head of Butterfly.
Fig. 147.—Section of Proboscis of butterfly showing lapping joint and dovetail joint.
Fig. 148.—Head of Butterfly (side view).
Figs. 141-148. Illustrated Study of Lepidoptera.—Study the stages in the development of codling moth, silkworm moth, and cabbage butterfly.
Where does each lay its eggs? What does the larva of each feed upon? Describe the pupa of each. Describe the adult forms. Find the spiracles and prolegs on the silkworm. Compare antennæ of moth and butterfly. Which has larger body compared to size of wings?
Describe the scales from a butterfly’s wings as seen under microscope (144). How are the scales arranged on moth’s wing (145)? By what part is scale attached to wing? Do the scales overlap?
Study butterfly’s head and proboscis (Figs. 146-148). What shape is compound eye? Are the antennæ jointed? Is the proboscis jointed? Why not call it a tongue? (See text.)
Which mouth parts have almost disappeared? What is the shape of cut ends of halves of proboscis? How are the halves joined to form a tube?
If you saw a butterfly on a flower, for what purpose would you think it was there? What, if you saw it on a leaf? How many spots on fore wing of female cabbage butterfly? (Fig. 124, above.)
Does the silkworm chrysalis fill its cocoon? Eggs may be obtained from U. S. Dept. of Agriculture.
Fig. 149.
Fig. 150.
Fig. 151.
Fig. 152.
Fig. 153.
Fig. 154.
Fig. 155.
Fig. 156.
Fig. 157.
Fig. 158.—Anatomy of bee.
Figs. 149-161. Illustrated Study of Bees and their Kindred.—Head of worker (Fig. 149): o, upper lip; ok, chewing jaws; uk, grasping jaws; kt, jaw finger; lt, lip finger; z, tongue.
How do heads of drone (150) and queen (151) differ as to mouth, size of the two compound eyes, size and position of the three simple eyes? Is the head of a worker more like head of drone or head of queen? Judging by the head, which is the queen, drone, and worker in Figs. 154-156? Which of the three is largest? Smallest? Broadest?
Figure 152 shows hind leg of worker. What surrounds the hollow, us, which serves as pollen basket? The point, fh, is a tool for removing wax which is secreted (c, Fig. 157) between rings on abdomen. In Fig. 158, find relative positions of heart, v, food tube, and nerve chain. Is crop, J, in thorax or abdomen? In this nectar is changed to honey, that it may not spoil. Compare nerve chain in Fig. 132.
Fig. 159.—Ichneumon fly.
Fig. 160.
Fig. 161.—Wasp using pebble.
From Peckham’s “Solitary Wasps,” Houghton, Mifflin & Co.
Compare the cells of bumble bee (Fig. 153) with those of hive bee. They differ not only in shape but in material, being made of web instead of wax, and they usually contain larvæ instead of honey. Only a few of the queens among bumble bees and wasps survive the winter. How do ants and honey bees provide for the workers also to survive the winter? Name all the social insects that you can think of. Do they all belong to the same order?
The ichneumon fly shown enlarged in Fig. 159 lays its eggs under a caterpillar’s skin. What becomes of the eggs? The true size of the insect is shown by the cross lines at a. The eggs are almost microscopic in size. The pupæ shown (true size) on caterpillar are sometimes mistaken for eggs. The same mistake is made about the pupa cases of ants. Ichneumon flies also use tree-borers as “hosts” for their eggs and larva. Is this insect a friend of man?
The digging wasp (Figs. 160 and 161) supplies its larva with caterpillars and closes the hole, sometimes using a stone as pounding tool. Among the few other uses of tools among lower animals are the elephant’s use of a branch for a fly brush, and the ape’s use of a walking stick. This wasp digs with fore feet like a dog and kicks the dirt out of the way with its hind feet.
Are the wings of bees and wasps more closely or less closely veined than the wings of dragon flies? (Fig. 177.) For an interesting account of the order “Joined-wings” (bees and their kindred) see Comstock’s “Ways of the Six-footed,” Ginn & Co.
Illustrated Study of Beetles.
Fig. 162.—Diving beetle (Dysticus), with larva, a.
Fig. 163.—Weevil.
Fig. 164.
Fig. 165.
Fig. 166.—Click beetle.
Fig. 167.—May Beetle.
Fig. 168.
Fig. 169.—Colorado beetle (potato bug).
Illustrated Study of Beetles (Figs. 162-169).—Write the life history of the Colorado beetle, or potato bug (Fig. 169), stating where the eggs are laid and describing the form and activities of each stage (the pupal stage, b, is passed in the ground).
Do the same for the May beetle (Figs. 167-168). (It is a larva—the white grub—for three years; hogs root them up.) Beetles, like moths, may be trapped with a lantern set above a tub of water.
Where does a Scarab or sacred beetle of the Egyptians, also called tumble bug (Fig. 164), lay its eggs (Fig. 165)? Why?
How does the click beetle, or jack snapper (Fig. 166), throw itself into the air? For what purpose?
The large proboscis of the weevil (Fig. 163) is used for piercing a hole in which an egg is laid in grain of corn, boll of cotton, acorn, chestnut, plum, etc.
How are the legs and body of the diving beetle suited for swimming (Fig. 162)? Describe its larva.
What is the shape of the lady bug (Fig. 97)? It feeds upon plant lice (Fig. 185). Is any beetle of benefit to man?
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.
Fig. 171.
Fig. 172.—Metamorphosis of house fly (enlarged).
Fig. 173.—Metamorphosis of flea.
Fig. 174.—Louse.
Fig. 175.—Bed bug. × 5.
Fig. 176.—Life history of mosquito.
Illustrated Study of Insect Pests (Figs. 171-176).—Why does the clothes moth (171) lay its eggs upon woolen 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. For figure see Human Biology, Chap. X. 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 odor?
Fig. 177.
Fig. 177. Illustrated Study of Dragon Fly.—3 shows dragon fly laying its eggs in water while poised on wing. Describe the larval form (water tiger). The extensible tongs are the maxillæ enlarged. The pupa (1) is active and lives in water. Where does transformation to adult take place (5)? Why are eyes of adult large? its legs small? Compare front and hind wings.
Do the eyes touch each other? Why is a long abdomen useful in flight? Why would long feelers be useless? What is the time of greatest danger in the development of the dragon fly? What other appropriate name has this insect? Why should we never kill a dragon fly?
Fig. 178.—The tarantula.
Fig. 179.—Trap-door spider.
Fig. 180.
Fig. 181.—Anatomy of spider.
Fig. 182.—Laying egg.
Fig. 183.—Foot of spider.
Illustrated Study of Spiders (Figs. 178-183).—The tarantula, like most spiders, has eight simple eyes (none compound). Find them (Fig. 178). How do spiders and insects differ in body? Number of legs? Which have more joints to legs? Does trap-door spider hold the door closed (Fig. 179)? How many pairs of spinnerets for spinning web has a spider (Spw, 180)? Foot of spider has how many claws? How many combs on claws for holding web? Spiders spin a cocoon for holding eggs. From what part of abdomen are eggs laid (E, 182; 2, 181)? Find spider’s air sacs, lu, Fig. 181; spinning organs, sp; fang, kf; poison gland, g; palpi, kt; eyes, au; nerve ganglia, og, ug; sucking tube, sr; stomach, d; intestine, ma; liver, le; heart, h, (black); vent, a. Give two reasons why a spider is not an insect. How does it place its feet at each step (Fig. 110)? Does the size of its nerve ganglia indicate great or little intelligence? Why do you think first part of body corresponds to both head and thorax of insects?
Fig. 184.—Squash bug, or stink bug.
The following Farmer’s Bulletins are available for free distribution to those interested, by the U. S. Department of Agriculture, Washington, D.C.:—
Farmer’s Bulletin No. 47, Insects affecting the Cotton Plant; No. 59, Bee Keeping; No. 70, The Principal Insect Enemies of the Grape; No. 80, The Peach Twig Borer; No. 99, Three Insect Enemies of Shade Trees; No. 120, The Principal Insects affecting the Tobacco Plant; No. 127, Important Insecticides; No. 132, The Principal Insect Enemies of Growing Wheat; No. 145, Carbon Bisulphid as an Insecticide; No. 146, Insecticides and Fungicides; No. 152, revised, Mange in Cattle; No. 153, Orchard Enemies in the Pacific Northwest; No. 155, How Insects affect Health in Rural Districts; No. 159, Scab in Sheep; No. 165, Silkworm Culture; No. 171, The Control of the Codling Moth; No. 172, Scale Insects and Mites on Citrus Trees; No. 196, Usefulness of the Toad; No. 209, Controlling the Boll Weevil in Cotton Seed and at Ginneries; No. 211, The Use of Paris Green in controlling the Cotton Boll Weevil; No. 212, The Cotton Bollworm; No. 216, The Control of the Boll Weevil; No. 223, Miscellaneous Cotton Insects in Texas; No. 247, The Control of the Codling Moth and Apple Scab.
Fig. 185.—Female plant louse, with and without wings (enlarged).
The following bulletins of the Bureau of Entomology may be obtained from the same source at the prices affixed: Bulletin No. 25 (old series), Destructive Locusts, 15c.; No. 1 (new series), The Honey Bee, 15c.; No. 3, The San José Scale, 10c.; No. 4, The Principal Household Insects of the U. S., 10c.; No. 11, The Gypsy Moth in America, 5c.; No. 14, The Periodical Cicada, 15c.; No. 15, The Chinch Bug, 10c.; No. 16, The Hessian Fly, 10c.; Nos. 19, 23, and 33, Insects Injurious to Vegetables, 10c. each; No. 25, Notes on Mosquitoes of the U. S., 10c.; No. 42, Some Insects attacking the Stems of Growing Wheat, Rye, Barley, and Oats, 5c.; No. 50, The Cotton Bollworm, 25c.; No. 51, The Mexican Boll Weevil, 25c.
Bureau of Plant Industry—Bulletin No. 88, Weevil-resisting Adaptations of the Cotton Plant, 10c. This gives an instructive account of the struggle of a plant for existence against an insect enemy.
Fig. 186.—Gall fly (enlarged) and oak gall with larva, and one from which a developed insect has escaped.
Fig. 187.—Plan of Mouth Parts of the Insect Orders. A, straight wings, nerve wings, false nerve wings; B, joined wings; C, scaly wings; D, half wings; E, two wings.
ol, upper lip; ok, biting jaws; uk, holding jaws; ul, under lip; kt, jaw fingers; lt, lip fingers.