Popular Science Monthly/Volume 27/June 1885/Moths and Moth-Catchers I
|MOTHS AND MOTH-CATCHERS.|
ONE day, in the British Museum, while waiting a moment in a room where entomological specimens were exhibited, I saw two workmen bending over a case containing butterflies and moths.
"There is the Camberwell Beauty," said one, pointing out a particular example to his companion.
"Ay!" was the ejaculatory response, and the tone of that "Ay!" I am not likely to forget. It took me at once to the speaker's probably humble home, stored with treasured specimens in their boxes, pinned down low, labeled and arranged. How many hours of stormy evenings had not been pleasurably spent in sorting and debating, in setting and classifying, these downy bits of Nature's finery! From how much worse employment may not these "little beauties" have saved their owner!
There is no doubt that in England, as well as in France and Germany, the collecting of moths is a very general recreation as compared with the United States. That it is harmless is a negative praise; that a pursuit of its objects is healthful, and takes the man who works in the city out into the fresh country air, is a positive recommendation. But the labor is also instructive. Things have now changed very much since the days of Malpighi, and biology is a respected and necessary study. And throughout the world of animated beings it may be safely said that the growth and changes of life can nowhere be so easily and pleasantly observed as in the rearing of butterflies and moths from the egg. As to butterflies, it may be asserted that they are less interesting than their cousins the moths, who constitute the elder branch of the great natural group of scaly-winged insects, or Lepidoptera, to which both belong. The butterflies are less numerous in species, or kinds, and more uniform in habit and appearance. These gaudy and papery-winged day-flies have their own attractions and present their own scientific problems, but in number, diversity, soft and delicate colors, and patterns and unexpected modes of life, they can not hold a candle, to speak both figuratively and appositely, to the foolish but lovely moths.
First, let us assure ourselves that by moths we do not mean clothes-moths. These terrors to the housekeeper are only of two or three kinds, and of small size, belonging to the genera Tinea and Tineola; while there are over seven thousand species of North American moths already in our catalogues, from the large and gorgeous "Regal Moth" (Citheronia regalis) to the "Tiny Gem" (Lithariapteryx), of all shades of color from gray to pink, from black to yellow, all innocent of carpetor clothes-eating in their young larval days. To some general statements as to these, the methods of hunting and preserving them, and those who carry on the fascinating pursuit, I claim the reader's indulgence for a few pages of what I shall try to make easy and instructive reading.
It is, perhaps, unnecessary to state that moths, like plants, bear, each kind, a particular double Latin or Latinized title, as Actias luna, the "American Moon-Moth," or "Queen of the Night." The first name is that of the genus, the second of the species. The genus is founded on certain particular points of structure, and usually embraces a number of kinds or species which share in these particular structural features. While the genus Actias, for instance, is known by its thinly scaled, pale-green wings, the hind pair furnished with twisted "tails," our species luna differs from a number of Asiatic and African species by certain marks and peculiarities of pattern and size.
These Latin names are a source of some difficulty to lay readers and to many amateurs. Some people prefer English names by which to designate their specimens, but our species have not been known for years, as have the European moths; consequently very few have received vernacular names. The "cotton-worm" (Aletia argillacea), and the "army-worm" (Heliophila unipuncta), are, indeed, two species of moths well known for their ravages in the larval state, and which are consequently provided with vernacular names by which they are distinguished. But we have no English names for the great majority of species, which are really different in kind from their transatlantic brethren.
The introduction of common names for our moths is evidently a matter not to be forced, but to be left to itself. The rule of priority, which Linnæus appointed to govern the Latin names, can not obtain here. Some of our butterflies have received several English names, as the common "milk-weed butterfly." Some of the names for moths in use in England are very pretty, such as the "Arches" and "Wainscots"; others are peculiar and less attractive, as the "Pugs" and "Lackies." English names for our moths will, it is to be hoped, gradually appear in our literature and come into general use. The vernacular names proposed in economic works, such as the reports of State entomologists, are often very ugly, and have nothing to recommend them. They are simple translations from the Latin in many cases, and are then quite often ridiculous. Dubiosa is translated doubtful; fraterna, fraternal, and so on; it is clear that the Latin names are much better than these. But see what lovely names they have in England for their moths: the "Kentish Glory," the "Peach Blossom," the "Buff Arches," the "Common Wainscot." About the vernacular names for our moths must come the cooling touch of time; they can not be struck out in the heat which accompanies the coining of a Latin name for a new species. Around their cradle some tutelary divinity must hover; some old tale, like an ancient crone, must be its nurse; out of some melody, dedicate to fields and flowers, must the words be taken which are to serve as the title for the new-comer. Affection for the object, quite distinct from the passion of the scientist, must have its part in the English name, which should also be apposite and express the appearance or habit of the moth. One of the names proposed for a North American species, Ommatostola Lintneri, appears to fill these conditions—viz., the "Dune Wainscot." It is a reed-colored moth, found on the sandy ridges (dunes) near the Long Island beaches. Again, another species, vividly colored, black, pink, and yellow, is called the "Spanish moth," as it bears the Spanish colors. Its scientific name is Euthisanotia timais. It breeds in Florida, and comes up our Atlantic coast-line in summer, being often beaten into the lighthouses with the birds, during wind-storms, or simply attracted by their light.
Our species of moths east of the Mississippi are pretty well known, and all but the very small ones, the Tineidæ or leaf-miners, are described in different publications. What a change during the twenty-five years which have just passed, and which span my own career as a catcher of moths! When, a boy of fifteen, I tried to find out the names of some of our moths, I had great difficulty in ascertaining that there was such a science as entomology at all! At that time, even in Agassiz's museum, at Cambridge, there were not fifty kinds labeled which had been described and named in this country. Now we have about seven thousand names of known species in our catalogues, and from one to two hundred are being added to the list every year. Our new discoveries come chiefly from the West, where wonderfully beautiful species are "turned up." Arizona and New Mexico, as well as Colorado, seem to be perfect paradises for rare and lovely moths.
The reader will have seen that there are two kinds of names, the scientific and the common. Nothing, it seems to me, that will promote popular interest in the study should be neglected; therefore I hope that pretty English names for our moths will appear and lighten the studies of many who find Latin difficult and ugly. It must be remembered, however, that when we wish to designate a certain kind of moth with precision, we are obliged to fall back upon the Latin name, and that there is a good deal of prejudice against common names by scientists, whose opinions are worthy of respect, but whose foible it is to be very exact and precise in their statements about a moth, or any object upon which they have special information, but who are otherwise as fallible as the rest of us when it comes to matters of conduct and art.
The old saying in natural history, that everything comes from an egg, holds good for moths. Nevertheless, modern science has wrought wonderful changes in our ideas on this subject since the days of Ray and Willoughby. The young are now considered as part and parcel of the old—a continuation, to some extent, of the bodies of their parents, whether we consider a moth or a man. The affinity between the seed of a plant and the egg of an animal is indeed illusory, but in some of the lower animals there is a process of reproduction allied to budding in plants. Years ago the poet Chamisso discovered the fact that the young of a lowly organized marine animal called Salpa did not resemble their parents. We know now that in some cases several generations intervene before the final form of the species is assumed. When we read of the discoveries in biology of Goethe and Chamisso, we see that there is some justice in the observation that it is the poet who understands Nature best. Perhaps we should rather conclude that the imagination is a quality which the naturalist can by no means dispense with. Goethe's theory of the true structure of the vertebrate skull is now accepted; Chamisso died before Steenstrup, in 1824, vindicated at least the general truth of his particular observations. A curious story is told of the first discoverer of the true nature of the coral makers. The French Academy of Sciences would not print his essay on the subject, and persisted in the old belief that the coral was a plant.
To return to our moth-eggs. While certain flies reproduce by a sort of budding in the larval state, our moths, so far as known, all come from eggs laid by the female moth on leaves, flowers, or the branches and trunks of trees. Some are inserted in crevices of the wood itself, and the little caterpillars, when they hatch, bore into the heart of the tree upon which they feed. The "peach-borer" (Ægeria exitiosa) and the "plum-borer" (Ægeria pictipes), Bailey's "goat-moth" (Cossus centerensis) are examples of certain kinds of wood-eating caterpillars. The little moth-eggs, usually attached singly, sometimes in belts and clusters, vary in the length of time which elapses before they hatch after they are laid. It is difficult to assert that there is any rule in this respect, and it is certainly hard to tell when they are "addled." When they are "bad" and fail to give the little worm, it is often because they are "stung" by minute four-winged flies, parasites upon these tiny objects.
One of the most curious things about the laying of moth-eggs is the botanical knowledge of the mother-moth. In the dark she knows the particular trees upon which her brood flourish, out of a whole forest. The proverb about one man's meat being another man's poison holds good when applied to the caterpillars of moths. They will starve, as a rule, before eating, or die upon eating, the wrong kind of leaves. The little eggs, sown here and there by the mother-moth in her nocturnal flights, are often very pretty to look at through the microscope, being adorned with delicate traceries. Some kinds are nearly smooth, as those of the Cecropia, which are quite easily found on lilac and other leaves, gummed on, with a little brown spot above, over the micropyle, through which the curled-up caterpillar within, a little black, thorny creature, escapes. Some caterpillars eat the empty egg-shell for their first meal, but the practice is far from general. Some which I particularly noticed, those of the "chestnut-stripe" or honeysuckle-leaves, only nibble at the empty egg-shell, and, I thought, were attracted by some of the softer parts which might remain. The caterpillars of this moth (Homohadena badistriga) afterward make a rather stout cocoon; I have reared them from eggs found in the back-yard of a house in the heart of New York city. So far do our country friends penetrate.
The bodies of caterpillars and moths are made up of segments, or rings, hardened by a substance called chitine, so that it has been said that insects really follow out Sydney Smith's suggestion, given under exceptional circumstances, and "sit in their bones" the whole time. They strike against the outside world with the knobby parts of their anatomy. A child once described a caterpillar as a "jointed tube, filled with soft stuff." I don't know how she found out about the "soft stuff," but the insides are soft, and, when carefully examined, show the respiratory canals, opening by little narrow slits in the sides of the segments (for insects do not breathe by the mouth), the nervous and the muscular systems, networks of little whitish threads, as also the central digestive apparatus, which takes up the most room, as our caterpillar is principally a feeding animal. The stiffness of the rings of insects is obviated by their being connected by a highly flexible membrane. The caterpillar increases in size by changing its skin. The old covering becomes too small to hold the food which is retained and transformed by the chemistry of the body into caterpillar-flesh. It splits behind the head, and, with more or less trouble, the caterpillar frees itself from it, stepping out, and leaving its old skin, a thin and almost colorless pellicle, to be blown by the summer winds into Nature's rag-bags which the spiders mostly carry about.
Caterpillars are of all colors, and, within certain limits, of all sizes, variations of the "jointed tube, with soft insides." They are plain and smooth, or ornamented with tufts of hair, or fleshy, colored humps; when young, the head and tail are somewhat swollen, and in this state one kind has been described as looking like "little animated dumbbells." When they attain their full size, they prepare to pass into the chrysalis state, and here their methods are equally diverse. A few hang themselves up by threads, like butterflies; others penetrate the ground, and, without any web, change into a naked, brown-colored pupa, which reposes in a sort of cell, made merely by the movement of the caterpillar pressing back the earth. This is the burial of Psyche. From it a host of oratorical and poetical figures are taken. It affords, in one way, even religious consolation. The human body, buried in the mold, gives to eternity and heaven the soaring soul, as the chrysalis, from its earthy cell, discloses the moth which beats the ether with unquiet wing. Again, many kinds of caterpillars spin thick cocoons, as the "American silk-worm" (Telea polyphemus), the "cecropia moth" (Platysamia cecropia), and the "sassafras emperor" (Callosamia Promethea). Many have been the efforts to utilize the silk thus made by our native moths, and interesting experiments are detailed with that spun by the American silk-worm, as published by Mr. Trouvelot. The silk of all these species can be no doubt used, because the Chinese and Japanese silk-worms belong to the same or nearly related genera. But none of them equal the original Indian or European silk-worm, the Bombyx mori, cultivated chiefly in the south of Europe, and which yields the silk of commerce. After several unsuccessful attempts, of late years, the rearing of the cocoons has been profitably undertaken in the United States, probably through the establishment of silk-mills and the protective tariff which stimulates the silk industry.
Everywhere in the country one may find the chrysalides of moths. Under stones, under moss, and beneath the loose bark of stumps, spun fast to branches and wrapped in the dead leaves of autumn, at the foot of the trees which fed the caterpillars, they may be found in all sorts of hiding-places. The duration of the apparently torpid chrysalis-life is different with the season and the species. From a few weeks to sometimes two years, the still nascent insects lie imprisoned. But at length the hour for escape arrives. The brown shell of the chrysalis splits, and the moth, struggling out of all its envelopes, crawls to some near foothold, where it may shake out and expand its feathery wings in safety. And then, when night comes, and the breeze, it gives itself to the darkness, braving all dangers, to deposit its eggs in safety and perpetuate its species, its main object accomplished often at the sacrifice of its own brief life.
While the moths are inseparably connected with the butterflies, we shall know them by their antennae not being knobbed at the tip, their more downy wings and body, their generally softer colors, and their usual sleepy habit in daytime, when they fold their wings and seek dark places for repose.
Except a few small groups, most of which I can not admit as forming distinct families, our North American moths may be divided into ten groups, to each of which the term "family" is applied, just as we have the same term given to certain similar groups of other animals, such as the birds or fishes. These ten families are: 1. The Sphingidæ, or "hawk-moths," of which we have 91 species in our territory; 2. The Ægeriadæ, or "clear-wings," of which there are catalogued about 120 sorts; 3. The Zygœnidæ, or "clear-spots," comprising over 60 kinds; 4. The Bombycidæ, or "spinners," of which there are more than 400 species; 5. The Noctuidæ, or "owlet-moths," with nearly 1,600 different kinds; 6. The Geometridæ, or "spanners," with 500 species; 7. The Pyralidæ, or "snout-moths"; and 8. The Tortricidæ, or "leaf-rollers," with over 400 kinds of each; 9. The Tlneidæ, or "leaf-miners"; and 10. The Pterophoridæ, or "feather-moths," the former a large family of minute and often brilliantly colored species, the latter a smaller one containing curious slender moths, having the wings split into feathery fingers or rays. These last two groups are very incompletely known.
[To be continued.]