They are generally small in size, with stout bodies, very quick and powerful in fight. They have six walking feet in both sexes. The tibiæ of the hind feet, with few exceptions, have spurs. The caterpillars are cylindrical, smooth, tapering forward and backward from the middle, and generally having large globular heads. For the most part they undergo transformation into chrysalids which have a girdle and an anal hook, or cremaster, in a loose cocoon, composed of a few threads of silk, and thus approximate the moths in their habits. The genus Megathymus has the curious habit of burrowing in its larval stage in the underground stems of the yucca.
To one or the other of these five families all the butterflies, numbering about six hundred and fifty species, which are found from the Rio Grande of Texas to the arctic circle, can be referred.
Scientific Names.—From what has been said it is plain to the reader that the student of this delightful branch of science is certain to be called upon to use some rather long and, at first sight, uncouth words in the pursuit of the subject. But experience, that best of teachers, will soon enable him to master any little difficulties which may arise from this source, and he will come finally to recognize how useful these terms are in designating distinctions which exist, but which are often wholly overlooked by the uneducated and unobservant. It is not, however, necessary that the student should at the outset attempt to tax his memory with all of the long scientific names which he encounters in this and similar books. The late Dr. Horn of Philadelphia, who was justly regarded, during the latter years of his life, as the most eminent student of the Coleoptera, or beetles, of North America, once said to the writer that he made it a religious duty not to try to remember all the long scientific names belonging to the thousands of species in his collection, but was content to have them attached to the pins holding the specimens in his cabinets, where he could easily refer to them. The student who is engaged in collecting and studying butterflies will very soon come, almost without effort, to know their names, but it is not a sin to forget them.
In writing about butterflies it is quite customary to abbreviate the generic name by giving merely its initial. Thus in writing about the milkweed butterfly, Anosia plexippus, the naturalist will designate it as "A. plexippus." To the specific name he will also attach the name of the man who gave this specific name to the insect. As Linnæus was the first to name this insect, it is proper to add his name, when writing of it, or to add an abbreviation of his name, as follows: "A. plexippus, Linnæus," or "Linn." In speaking about butterflies it is quite common to omit the generic name altogether and to use only the specific name. Thus after returning in the evening from a collecting-trip, I might say, "I was quite successful to-day. I took twenty Aphrodites, four Myrinas, and two specimens of Atlantis." In this case there could be no misunderstanding of my meaning. I took specimens of three species of the genus Argynnis—A. aphrodite, A. myrina, and A. atlantis; but it is quite enough to designate them by the specific names, without reference to their generic classification.
Synonyms.—It is a law among scientific men that the name first given to an animal or plant shall be its name and shall have priority over all other names. Now, it has happened not infrequently that an author, not knowing that a species has been described already, has redescribed it under another name. Such a name applied a second time to a species already described is called a synonym, and may be published after the true name. Sometimes species have had a dozen or more different names applied to them by different writers, but all such names rank as synonyms according to the law of priority.
Popular Names.—Common English names for butterflies are much in vogue in England and Scotland, and there is no reason why English names should not be given to butterflies, as well as to birds and to plants. In the following pages this has been done to a great extent. I have used the names coined by Dr. S.H. Scudder and by others, so far as possible, and have in other cases been forced myself to coin names which seemed to be appropriate, in the hope that they may come ultimately to be widely used. The trouble is that ordinary people do not take pains to observe and note the distinctions which exist among the lower animals. The vocabulary of the common farmer, or even of the ordinary professional man, is bare of terms to point out correctly the different things which come under the eye. All insects are "bugs" to the vulgar, and even the airy butterfly, creature of grace and light, is put into the same category with roaches and fleas. Apropos of the tendency to classify as "bugs" all things which creep and are small, it may be worth while to recall the story, which Frank Buckland tells in his "Log-book of a Fisherman and Naturalist," of an adventure which he had, when a school-boy, at the booking-office of the London, Chatham, and Dover Railway Company in Dover. He had been for a short trip to Paris, and had bought a monkey and a tortoise. Upon his return from sunny France, as he was getting his ticket up to London, Jocko stuck his head out of the bag in which his owner was carrying him. The ticket-agent looked down and said, "You will pay half-fare for him." "How is that?" exclaimed young Buckland. "Well, we charge half-fare for dogs." "But this is not a dog," replied the indignant lad; "this is a monkey." "Makes no difference," was the answer; "you must pay half-fare for him." Reluctantly the silver was laid upon the counter. Then, thrusting his hands into the pocket of his greatcoat, Buckland drew forth the tortoise, and, laying it down, asked, "How much do you charge for this?" The ancient receiver of fares furbished his spectacles, adjusted them to his nose, took a long look, and replied, "We don't charge nothin' for them; them 's insects." It is to be hoped that the reader of this book will in the end have a clearer view of facts as to the classification of animals than was possessed by the ticket-agent at Dover.