BOOKS ABOUT NORTH AMERICAN BUTTERFLIES _Early Writers._--The earliest descriptions of North American butterflies are found in writings which are now almost unknown, except to the close student of science. Linnæus described and named a number of the commoner North American species, and some of them were figured by Charles Clerck, his pupil, whose work entitled "Icones" was published at Stockholm in the year 1759. Clerck's work is exceedingly rare, and the writer believes that he has in his possession the only copy in North America. Johann Christian Fabricius, a pupil of Linnæus, who was for some time a professor in Kiel, and attached to the court of the King of Denmark, published between the year 1775 and the year 1798 a number of works upon the general subject of entomology, in which he gave descriptions, very brief and unsatisfactory, of a number of North American species. His descriptions were written, as were those of Linnæus, in the Latin language. About the same time that Fabricius was publishing his works, Peter Cramer, a Dutchman, was engaged in giving to the world the four large quartos in which he endeavored to figure and describe the butterflies and moths of Asia, Africa, and America. Cramer's work was entitled "Papillons Exotiques," and contained recognizable illustrations of quite a number of the North American forms. The book, however, is rare and expensive to-day, but few copies of it being accessible to American students. Jacob Hübner, who was born at Augsburg in the year 1761, undertook the publication, in the early part of the present century, of an elaborate work upon the European butterflies and moths, parallel with which he undertook a publication upon the butterflies and moths of foreign lands. The title of his work is "Sammlung Exotischer Schmetterlinge." To this work was added, as an appendix, partly by Hübner and partly by his successor and co-laborer, Karl Geyer, another, entitled "Zuträge zur Sammlung Exotischer Schmetterlinge." The two works together are illustrated by six hundred and sixty-four colored plates. This great publication contains some scattered figures of North American species. A good copy sells for from three hundred and fifty to four hundred dollars, or even more.