Exquisite sails

Fragile, enchanting sails dip and dart, frolicking past in effervescent flight. Suddenly, the brightly colored wings whirl downward to cease momentarily in their merry garden ballet. Dainty legs cling to flower petals. Antennae guide the seeker toward odors of nectar. A carefully protected tongue is uncoiled and slipped into the blossom. A minute drop of nectar is drawn upward. Then, fluttering wings again carry the gaily colored visitor away to alight on another petalled dinner plate.

Seldom has nature invented anything quite so wonderful as the butterfly. Flitting and gliding from bloom to bloom, they present the very exuberance of life itself. But these delicate creatures have not always had their chromatic wings. It has been a rise to perfection in an insect Cinderella manner.

For, first, the insect starts as an egg, which in turn hatches into a larva. Then the larva passes into a dormantphase, the pupa or chrysalis. At the completion of this stage the butterfly emerges-a miracle of flashing, fragile wings.

Though frail they may seem, these same thin vanes of color propel some species on migrations spanning several thousand miles. The monarch butterfly, Danias plexiplus, for instance, amber brown, with striking black veins branched throughout the wing, yearly completes a junket which may start in northern Canada.

In route, huge flocks gather and migrate in mass, often going as far south as Mexico's southernmost points. Favoring the same rest stops year after year, the wanderers descend in spectacular clouds of color to shelter in these leafy hostels. Staying overnight, and maybe a day or two more, the travelers then drift onward, ever farther south.

Winter is a leisurely affair as they bask through luxuriant, tropical days. When spring comes, the impelling urge to wing northward overwhelms each member until all leave. The return leg of their journey is

Story and Photographs by WILLIS PETERSON

made in more of an individualistic manner. Obviously, many do not complete the whole trip, and thus we find monarchs which stop to breed and lay eggs along the length of the migratory flyway. With such tremendous flying capabilities it is not any wonder the monarch has attempted and succeeded in making ocean crossings. A number of the Pacific islands are now populated with these regal citizens. Presumably, they have come from North America, their native land. In contrast to the monarch's travel itinerary, which he has carefully plotted out in advance, the painted lady, Vanessa cardui, flock together but make erratic mass flights. However, the migration does relieve the pressure of overpopulation in those given areas, and perhaps this is what the movement is meant to be. The monarch is aptly named, but if he is king, certainly the swallowtail is the crown prince. The black swallowtail, Papilio philenor, is a dashing blade, attired in formal black, complete with after-dinner tails. On the outside of his tunic he displays a chain of orangish spots not unlike a flamboyant row of campaign ribbons. Standing out against the dark cut of his raiment they portray him as a chevalier d'arms. Two more of the Papilios, turnus and daummus, are known as the tiger swallowtails, with which we are all familiar. Both are costumed in gaudy saffron-yellow dress hemmed in black. Stately and haughty, their deliberate flight is an inspiring sight. There are more than twenty species of swallowtails native to North America. In all, more than 500 species populate the earth. Most are tropical. Like all butterflies, the swallowtails are fond of water, and during dry spells they can be seen congregating in camp meeting style around puddles of water. Endowed with long tongues, the Papilio tribe are able to penetrate deep-throated flowers for nectar which otherwise would have to be passed by. The giant swallowtail, Papilio thoas, often called the citrus swallowtail, measuring five inches or more across the wings, is one of the largest butterflies in the United

States. Large wings and flash of yellow make it conspicuous when flying against the sombre green of the orange trees.

The mourning cloak, Nymphalis antiopa, a medium-sized butterfly, demurely frocked in Sabbatical black edged in gold, actually hibernates in hollow logs and other well-protected places during winter, an interesting feat to contemplate. Imagine, thin wings, not any thicker than a sheet of paper maintaining their vitality throughout a period of six months of extreme cold. Also found in Europe, this exceedingly strong flyer occasionally sojourns to England, crossing the Channel and portions of the North Sea. It, no doubt, navigates one of the most turbulent air lanes in the world.Some burterflies are real home bodies, never straying more than a few hundred yards from where they were born. Thus, by not leaving their original ori breeding place they form colonies. One may travel several miles before finding another populated area of the same species.

Scientifically, butterflies and moths comprise the Order of Lepidoptera, numbering more than 100,000 species, the second largest group of insects in the world. In size they range considerably, from less than ½ inch across to more than forty square inches in wing area. They are found wherever there is plant food, from both Arctic regions through the tropics, and including most of the deserts. Life span of adults varies greatly in both butter flies and moths, from several hours, to, perhaps, two years for those that migrate.

The three principal segments of the insect are head, thorax and abdomen. moths and butterflies are equipped with six legs and two antennae. Legs and wings are attached to the thorax.

The antennae serve primarily as organs of scent, though there are scientists who now feel that they may play a far more important role in the receiving of sound waves, particularly true in the case of moths. Their feathery antennae with such huge sensory areas are indicative of this theory.

The adult's eyes are compound, that is, there are dozens of tiny eyes which form one large organ. The butterfly can see and determine movements quite well, though in the larva stage sight is only rudimentary.

The complete metamorphic cycle of this Order, the egg, the larva, the pupa and the butterfly or moth, is an efficient and highly specialized creation, where each stage of development eliminates competition for the adult form. All the larvae have chewing mouth parts, but in the adult form, all have a tubular proboscis, which can be likened to an ordinary soda fountain straw. Most of the larvae eat plants in a variety of ways, while the adults sip nectar, or may not eat at all, existing only on stored food within their bodies. The larvae span a gamut from consumers of decayed material to those that bore into trees, though most are content to eat green plant food.

The caterpillar is an obese fellow. When his appetite becomes so enormous that not another mouthful can be forced down, he merely discards his old tight skin and emerges in a new, loose one. In this muu muu he eats and eats until the elasticity of this garment is entirely filled out. The moult is repeated four to five times until the larva is ready to pupate.

Inside the pupa or chrysalis marvelous changes take place until the once-lowly worm is transformed into the adult. Shells of the pupa and chrysalis are hard and durable enough to withstand the rigors of blizzards, subzero temperatures, sleet and ice. Many pupa are cradled in cocoons, woven by the caterpillar for protection during this period.

When the adult emerges from this confining capsule he slowly pumps life-giving liquid into the veins of his wings. The stiffening veins in turn stretch and unfold the colorful membranes. Wings are entirely covered with tiny scales and are the main characteristic that all the adult insects have in common. They must be viewed with a microscope to be examined individually.

In fact, the Greek root derivation "lepis" meaning scale, and "preron" meaning wing, give the Order its designation. Presence of these microscopic flakes may easily be seen as dust by rubbing a finger on the wing surfaces. The colored residue is all composed of scales. Fastened at one end only, they are lapped over each other like the shingles on a roof. Flared, scalloped or spearlike, each may be shaped in a variety of ways.

The scales play an important function in formation of the insect's color design. Coloring in all butterflies and moths is of two types, strucrural and pigmented. The lovely iridescent hues we see playing on the wings when our angle of vision changes constitutes the physical or structural way. It is caused by the passage of light through the air into another medium, in this case, the structures contained in the scales. Refracting the light into tinted rays, these structures act somewhat like prisms. For instance, the colors we see displayed on the surface of soap bubbles are caused by refraction of light where the light's rays enter a different medium. A thin film of oil floating on top of water causes the same phenomenon.

The result is an appearance of color though there may be little or no coloring matter present. A large percent of coloration in their wings is due to this structural form.

This iridescence can be many times enhanced and deepened by addition of pigmented tones, particularly noticeable when sunlight strikes their wing surfaces at oblique angles. A simple experiment to determine whether or not the color of the wing is structural, or pigmented, or both can be made by blotting carbon tetrachloride onto a specimen's wing. If the color is structural it will instantly change hue. When the wing dries, however, all the original coloration will be present again. Since this solution dries rapidly, it makes a simple test.

In the case of solid colors, pigments are formed and deposited in the scales during the last days of the pupa development.

During the millions of years in which Lepidoptera have evolved, more use has been placed upon the front wing. As a consequence, the hind wing has become Continued on page twenty-seven