Part 1

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THE BUTTERFLY GUIDE

THE BUTTERFLY GUIDE

A POCKET MANUAL FOR THE READY IDENTIFICATION OF THE COMMONER SPECIES FOUND IN THE UNITED STATES AND CANADA

BY

W. J. HOLLAND, LL.D.

Director of the Carnegie Museum Author of “The Butterfly Book,” “The Moth Book,” etc.

_With 295 Colored Figures_ _Representing 255 Species and Varieties_

Garden City New York DOUBLEDAY, PAGE & COMPANY 1915

_Copyright, 1915, by_ DOUBLEDAY, PAGE & COMPANY

_All rights reserved, including that of translation into foreign languages, including the Scandinavian_

To the BOY SCOUTS OF AMERICA I dedicate this Book _The Author_

PREFACE

Recent advances in the arts make it possible to illustrate books at much less cost than formerly. An important invention is the process of printing in three colors from half-tone plates. The author of this manual was one of the first to use this process in illustrating a work upon the lepidoptera. When “The Butterfly Book” appeared he received letters from many scientific friends expressing their wonder. Among those who wrote to him was Dr. Samuel Hubbard Scudder, the Nestor among American lepidopterists, who has since passed away. He said: “I am simply astonished at the fidelity to nature displayed by the plates in your book, and at the low price at which the new process permits it to be sold.”

That “The Butterfly Book” met a real need is shown by the fact that more than thirty thousand copies have already found purchasers. It is, however, a biggish book. The publishers, Messrs. Doubleday, Page & Co., have asked me to get up a little pocket manual of the butterflies, similar in form to the “Flower Guide,” which has been most cordially received by the public. I have therefore prepared the following pages, to which in the gracious phrase of our forefathers I now “invite the attention of the gentle reader.”

There are more than six hundred species of butterflies found in North America, north of the Gulf of Mexico and the Rio Grande. Most of these are figured in “The Butterfly Book.” In this manual two hundred and fifty-five species and varieties are depicted in their natural colors. They are mainly the commoner forms, which occur in the more densely inhabited parts of the United States and Canada. I have, however, included numerous forms from the Southern States, and not a few of the more showy species from the Pacific Coast.

In some cases only half of the insect is shown. “Half a loaf is better than no bread.” In some cases only one side of the wings is delineated. Usually this is sufficient for identification. The inhabitants of this earth have never seen but one side of the moon, but they know it when they see it, unless they be like the tipsy pair, one of whom said to the other, who was leaning against a lamp post, “Friend, is that the moon, or a lamp?” and who received the reply: “Don’t ask me, I’m a stranger myself in these parts.” By showing only one half, or one side, of a species I have been able to illustrate many more than I could otherwise have done.

The figures of some of the larger species have been slightly reduced to accommodate them to the page, but as the natural size is always given in the description the student need not be perplexed.

The author hopes that his readers will have as much pleasure in studying the winged fairies of the woods and the fields as he has had in preparing this small pocket guide for their assistance.

INTRODUCTORY

THE PLACE OF BUTTERFLIES IN THE ANIMAL KINGDOM

The Animal Kingdom is divided into various _subkingdoms_. One of these is the subkingdom of the _Arthropoda_. This word is derived from the Greek nouns ἄρθρον (_arthron_) meaning _joint_, and πούς (_pous_) meaning _foot_. The _Arthropoda_ are animals the bodies of which are made up of a series of rings or segments jointed together, and the other organs of which are likewise composed of tubular bodies similarly united. All arthropods are _invertebrates_; that is to say, they do not have backbones and internal skeletons, such as are possessed by fishes, reptiles, birds, and mammals, including man. Vertebrate animals have _endoskeletons_, “inside skeletons.” In a ham, for instance, the bone is internal to the muscular parts, or meat, and lies near the middle. The muscles of a man clothe his bones. In the arthropods, on the contrary, the hard parts clothe the muscles. Arthropods are therefore said to have _exoskeletons_, “outside skeletons.” The body, the legs, and other organs of an insect or a crab consist of a series of hollow tubes held together by flexible skin at the points of union, and controlled in their movements by muscles which pull from the inside. The meat of a lobster is inside of the shell, or exoskeleton, as everybody who has eaten a lobster knows. The arrangement is exactly the reverse of that which we find in the vertebrates.

EXPLANATION OF PLATE A

Fig. a. _Magnified scales of butterflies._ 1, ordinary scale of _Papilio_; 2, do. of _Colias_; 3 _androconium_, or scale from wing of male _Neonympha eurytus_; 4, do. of male _Pieris oleracea_; 5, do. of male _Lycæna pseudargiolus_ (Figs. 1-2 after Verity; Figs. 3-5 after Scudder).

Fig. b. Patch of scales on wing of _Pieris napi_ (after Verity).

Fig. c. Body of _Anosia plexippus_.

I. Head. 1, antenna; 2, eye; 3, proboscis; 4, palpus; cl. clypeus; o, occiput.

II. Thorax. 5, prothoracic leg; 6, mesothoracic leg; 7, metathoracic leg; e, e, e, episterna; c, c, c, coxæ; tr., tr., trochanters of last two legs; f, f, femora of do.; s, s, s, scuta of first, second, and third segments of thorax.

III. Abdomen. 1-9 segments; sp., sp., spiracles (after Burgess).

Fig. d. Head and legs of _Œneis semidea_, showing aborted front leg.

Fig. e. Palpus of _Argynnis aphrodite_.

Fig. f. Leg of _Argynnis idalia_. 1, coxa; 2, trochanter; 3, femur; 4, tibia; 5, tarsus.

Fig. g. Knobbed antenna of _Argynnis idalia_.

Fig. h. Clubbed antenna of _Basilarchia astyanax_.

Fig. i. Hooked antenna of _Amblyscirtes vialis_.

[Illustration: PLATE A]

The subkingdom of the _Arthropoda_ is divided into six _classes_, one of which consists of the _Insecta_ (insects). It is estimated that there are three and a half millions of species of insects upon the globe, not to speak of the vast number of species which are now extinct, and known only by their fossil remains.

The Class _Insecta_ is subdivided into many _Orders_. To attempt even to briefly speak of all these orders would take more space than the publisher has allotted to the author, and it is enough to say that butterflies belong to the order _Lepidoptera_. The lepidoptera are divided into two _Suborders_: the _Rhopalocera_, or Butterflies, and the _Heterocera_, or Moths. Both are characterized by having scaly wings, hence the name, which is derived from the Greek words λεπὶς (_lepis_) meaning _scale_, and πτερὸν (_pteron_) meaning _wing_. Lepidoptera are “scale-winged insects.” Any one who has ever handled a butterfly or moth, must have noticed upon his fingers a dust-like substance, rubbed off from the wings of the captured insect. Upon examining this substance under a microscope it is seen to be composed of minute scales (see Plate A, Fig. _a_), and upon looking at the wing of a butterfly under a magnifying glass it is seen to be covered with such scales, arranged somewhat as the scales upon the sides of a fish, or as the shingles upon the roof of a house (see Plate A, Fig. _b_).

Butterflies are mainly diurnal in their habits, preferring the sunshine. Moths on the other hand are nocturnal, and fly in the dusk, or after dark. Butterflies are therefore often called _diurnal lepidoptera_, and moths are spoken of as _nocturnal lepidoptera_. There are, however, a few butterflies which fly at dusk, and there are many moths which are diurnal in their habits. Such moths are generally gay in color, and for the most part inhabit tropical countries, although we have a few such species in the United States. Ordinarily the best way to distinguish between butterflies and moths is by examining their antennæ, or “feelers,” as they are sometimes incorrectly called. In the case of butterflies the antennæ are thread-like, terminating in a small _knob-like_, or _club-like_ enlargement. It is this fact which has led naturalists to call them _Rhopalocera_. The word is derived from the Greek nouns ῥώπαλον (_rhopalon_) meaning a _club_, and κέρας (_keras_) a _horn_. _Butterflies are lepidoptera having at the end of their antennæ clubs, which are sometimes short, long, or hooked_ (see Plate A, Figs. _g_, _h_, _i_.) The forms assumed by the antennæ of moths are very various. The moths are therefore known as _Heterocera_, the word being compounded from the Greek adjective ἕτερος (_all sorts_) and the noun κέρας (_keras_) a _horn_. _Moths are lepidoptera having all sorts of antennæ, except such as are club-shaped at their ends._ However there is no rule without its exceptions, and there are a few rare moths in tropical lands which have club-shaped antennæ like butterflies, but none of these occur in the region with which this book deals.

THE ANATOMY OF BUTTERFLIES

The body of a butterfly consists of the head, the thorax, and the abdomen (see Plate A, Fig. _c_).

The head carries two relatively large eyes, one on either side. The eyes of insects are compound, and if examined under a microscope are seen to have a multitude of minute facets, which serve to gather the light from all directions, so that butterflies can look forward and backward, upward and downward, as well as outward, all at one time. Between the eyes on the upper part of the head arise the antennæ, of which we have already spoken. The precise function of these organs in insects has been the subject of much discussion. Supposed by some to be ears, by others to be the seat of the sense of smell, by others to combine within themselves these two senses, and by still others to represent a sense which is not possessed by vertebrate animals, their use in the life of insects is not yet clearly understood. The weight of evidence seems to be in favor of the view that they are organs of smell, and it is now quite firmly established by experiment that the organs of hearing in insects are represented by certain pores and openings on their legs. In front between the eyes and below the antennæ are two little organs, each composed of three joints, which are known as the _labial palpi_ (see Plate A, Fig. _e_). Between these, coiled up like a watch-spring, is the proboscis, with which the butterfly sucks up the nectar from flowers or drinks water from moist places (see Plate A, Figs. _c_ and _d_). We have not the space in this little manual to go more deeply into the anatomy of these organs, but enough has been said to enable the beginner to recognize the various parts. The student realizes that the head in general supports the principal organs of sense and the proboscis, or mouth.

The thorax carries the organs of locomotion, which consist of four wings and six feet. The thorax is made up of three segments, or rings, the foremost of which is called the _prothorax_, the next the _mesothorax_, and the hindmost the _metathorax_. The subdivisions of the thorax are not easily distinguishable by examining the body of a butterfly even under a microscope, because the bodies of butterflies are generally heavily clothed with hairs and scales. In order to clearly make out the subdivisions, which we are considering, it is necessary to take a specimen and denude it of its scales and hairs, and even dissect it under a glass. The correctness of the foregoing statements then becomes apparent.

The legs of butterflies are arranged in three pairs, the foremost of which are known as _prothoracic_, being attached to the prothorax; the second pair are called _mesothoracic_, springing, as they do, from the middle segment of the thorax; and the last are styled _metathoracic_ legs, rising from the hindmost segment of the chest (see Plate A, Fig. _c_). It should be noted here that in the great family of the _Nymphalidæ_, or “Brush-footed Butterflies,” in both sexes the anterior, or prothoracic pair of legs, are not fully developed, being aborted (see Plate A, Fig. _d_) and therefore do not serve for walking; and that in the families of the _Erycinidæ_, or “Metal-marks,” and the _Lycænidæ_, or “Blues and Coppers,” the females have six legs adapted to walking, while the males possess only four ambulatory legs, the front pair being in the latter sex aborted in these families, as in the _Nymphalidæ_. The legs of butterflies, like those of all other insects, consist of five parts (see Plate A, Fig. _f_) the first of which, nearest the body, is called the _coxa_, with which articulates a small ring-like piece, known as the _trochanter_. To the trochanter is attached the _femur_, and united with the latter, forming an angle with it, is the _tibia_. The last division of the leg is the _tarsus_, or foot, composed of a series of joints, to the last of which is attached a pair of claws, which in butterflies are generally rather minute, though in other orders of insects these claws are sometimes long and powerful, this being especially true of some beetles. The prothoracic legs of the _Nymphalidæ_ and of the males of the _Erycinidæ_ and _Lycænidæ_ have lost the use of the tarsus, only retaining it in feeble form, and the tibia has undergone modification. In many of the _Nymphalidæ_ the tibia is densely clothed with long hairs, giving this part of the leg the appearance of a brush, whence the name “Brush-footed Butterflies” (see Plate A, Fig. _d_). The tibiæ are often armed with more or less strongly developed spines.

The most striking parts of butterflies are their wings, which in proportion to the size of their bodies are usually very large, and which are remarkable for the beauty of the colors and the markings which they display both on the upper and on the under side.

The wings consist of a framework of horny tubes which are in reality double, the inner tube being filled with air, the outer tube with blood. The blood of insects is not, like that of vertebrates, red in color. It is almost colorless, or at most slightly stained with yellow. The circulation of the blood in the outer wall of the wing-tubes takes place most freely during the brief period in which the insect is expanding its wings after emergence from the chrysalis, concerning which we shall have more to say elsewhere. After the wings of the butterfly have become fully expanded, the circulation of the blood in the wings ceases almost entirely. The horny tubes, which compose the framework of the wings of butterflies, support between them a delicate membrane, to which upon both the upper and lower sides are attached the scales. The two fore wings are more or less triangular in outline; the hind wings are also subtriangular, but are generally more or less rounded on the outer margin, and in numerous forms are provided with tails or tail-like prolongations.

Inasmuch as in describing butterflies authors generally devote a good deal of attention to the markings of the wings, it is important for the student to become acquainted with the terms employed in designating the different parts of the wings (see Plate B, Fig. 10). That part of the wing which is nearest to the thorax, is called the _base_; the middle third of the wing is known as the _median_ or _discal area_; the outer third as the _external_ or _limbal area_. The anterior margin of the wing is called the _costal margin_; the outer edge is styled the _external margin_; the inner edge is known as the _inner margin_. The tip of the front wing is called the _apex_, which may be rounded, acute, falcate (sickle-shaped), or square (see Plate B, Figs. 1-4). The angle formed by the outer margin of the front wing with the inner margin is commonly known as the _outer angle_. The corresponding angle on the hind wing is known as the _anal angle_, and the point of the hind wing, which corresponds with the tip or apex of the fore wing, is designated as the _external angle_. The margins of wings may have different styles of outline, and are spoken of as entire, crenulate, scalloped, waved, lobed, or tailed (see Plate B, Figs. 5-8).

A knowledge of the veins which form the framework of the wings is important, because authors have frequently established genera upon the basis of the wing structure. It is desirable on this account to understand the nomenclature which has been applied to the veins. This nomenclature is somewhat variant, different writers having employed different terms to designate the same vein. In what follows the writer has adopted the designations which are most current, and which are generally accepted by authors. The best understanding of this matter is to be derived from the attentive study of the diagrams given on Plate B, Figs. 9 and 10. The veins in both the fore and hind wings of butterflies may be divided into simple and compound veins. In the fore wing the simple veins are the _costal_, the _radials_, the _submedian_, and the _internal_; in the hind wing they are the _costal_, the _subcostal_, the _radials_, the _submedian_, and the _internal_. The costal vein in the hind wing is, however, generally provided near the base with a short ascending branch, which is known as the _precostal_ vein. In addition to the simple veins there are in the fore wing two branching veins, one immediately following the costal, known as the _subcostal_, and the other preceding the submedian, known as the _median_. The branches of these compound veins are known as _nervules_. The median vein always has three nervules. The nervules of the subcostal veins branch upwardly and outwardly toward the costal margin and the apex of the fore wing. There are always from four to five _subcostal nervules_, variously arranged. In the hind wing the subcostal is simple. The median vein in the hind wing has three nervules, as in the fore wing. In both wings between the subcostal and the median veins toward the base is enclosed the _cell_, which may be either _closed_ or wholly or partially _open_ at its outer extremity. The veinlets which close the cell are known as the discocellular veins, of which there are normally three. From the point of union of these _discocellular veins_ go forth the _radials_, known respectively as _upper_ and _lower_, though the upper radial in many genera is emitted from the lower margin of the subcostal vein.

EXPLANATION OF PLATE B

Fig. 1. _Angulated_ or _acuminate apex_ of fore wing (_Grapta_).

Fig. 2. _Falcate apex_ of fore wing (_Pyrrhanæa_).

Fig. 3. _Square apex_ of fore wing (_Smyrna_).

Fig. 4. _Rounded apex_ of fore wing (_Euptoieta_).

Fig. 5. Hind wing _rounded at outer angle, twice-tailed_ (_Thecla_).

Fig. 6. Hind wing _crenulate, tailed, lobed at anal angle_ (_Papilio_).

Fig. 7. Hind wing with _outer margin entire_ (_Parnassius_).

Fig. 8. Hind wing with _outer margin waved_ (_Argynnis_).

Fig. 9. Neuration of wings of _Anosia plexippus_.

_Veins_: C, costal; SC, subcostal; M, median; SM, submedian; I, internal; PC, precostal; UDC, upper discocellular; MDC, middle discocellular; LDC, lower discocellular; UR, upper radial; LR, lower radial.

_Nervules_: SC 1, 2, 3, 4, 5, first to fifth subcostal nervules; M 1, 2, 3, first to third median nervules.

Fig. 10. Wing of _Papilio turnus_, showing the names given to the different parts of the wings of butterflies.

[Illustration: PLATE B]

Butterflies generally hold their wings erect when they are at rest, with their upper surfaces facing each other, and only the under surfaces displaying their colors to the eye. In the genus _Ageronia_ the insect prefers, like some moths, to settle upon the bark of trees, with the wings spread flat, and the head pointing downward. Many of the _Hesperiidæ_, or “Skippers,” have the habit when they are at rest of holding the fore wings folded together, while the hind wings are expanded horizontally. Many of the butterflies known as “Hair-streaks,” belonging to the genus _Thecla_ and its allies, have the curious habit, when at rest upon the end of a twig or leaf, of moving their folded wings backward and forward, first on one side and then on the other, thus partially displaying with each movement the splendid blue surfaces of the upper side of the wings.

The abdomen of butterflies consists normally of nine segments (see Plate A, Fig. _c_). In most butterflies except the Ithomiids, the end of the abdomen does not extend beyond the anal angle of the hind wings. In the moths, on the other hand, there are multitudes of genera in which the extremity of the abdomen extends far beyond the hind margin of the posterior wings. This is particularly true of the hawk-moths. A minute examination of the abdomen of a butterfly reveals in each segment except the last a little valve-like orifice on either side. These openings are known as _spiracles_ (see Plate A, Fig. _c_). Through these the insect breathes. Insects do not breathe through their mouths, like vertebrates, and their lungs, or what correspond to the lungs of the higher animals, are not located in the thorax or chest, but in the abdomen. The last segment of the abdomen carries at its extremity the external organs of generation. The male may be distinguished from the female by the so-called _prehensores_, or “claspers,” two flattish, scale-like appendages which adhere one on either side to the last segment of the body. These organs are quite peculiar in their structure, and in recent years have received a great deal of study, as it has been found possible by means of them to distinguish closely allied species, especially among the _Hesperiidæ_. It is, however, not possible within our allotted space to go into a minute discussion of this matter. The abdomen of the female is devoid of these appendages, and in this sex is generally heavier and plumper, especially when the eggs, which fill the ovaries, have not as yet been deposited.

Thus far we have devoted our attention almost exclusively to the consideration of the external organs of the suborder of insects which is under discussion. It may be of interest to devote a few paragraphs to the internal anatomy of butterflies. To do the subject full justice would require a volume; nevertheless some general statements may pave the way for a more studious inquiry on the part of readers.