This is a reproduction of a library book that was digitized by Google as part of an ongoing effort to preserve the information in books and make it universally accessible. https://books.google.com ENTOMOLOGY, FISHERIES AND WILDLIFE LIBRARY lepartmwtt of Agrtrttltur* Ohum 5"£f 5". 7 5" look I j MARCH. 1916 BULLETIN 372 CORNELL UNIVERSITY AGRICULTURAL EXPERIMENT STATION OF THE NEW YORK STATE COLLEGE OF AGRICULTURE Beverly T. Galloway. Director Department of Entomology REPORTS ON SCALE INSECTS By John henry comstock Professor of F.ntomology, Emeritus, in Cornell University, and formerly Entomologist of the United States Department of Agriculture PUBLISHED BY THE UNIVERSITY ITHACA. NEW YORK CORNELL UNIVERSITY AGRICULTURAL EXPERIMENT STATION Experimenting Staff BEVERLY T. GALLOWAY, B.Agr.Sc, LL.D., Director. HENRY H. WING, M.S. in Agr., Animal Husbandry. T. LYTTLETON LYON, Ph.D., Soil Technology. JOHN L. STONE, B.Agr., Farm Practice. JAMES E. RICE, B.S.A., Poultry Husbandry. GEORGE W. CAVANAUGH, B.S., Agricultural Chemistry. HERBERT H. WHETZEL, M.A., Plant Pathology. ELMER O. FIPPIN, B.S.A., Soil Technology. G. F. WARREN, Ph.D., Farm Management. WILLIAM A. STOCKING, Jr., M.S.A., Dairy Industry. WILFORD M. WILSON, M.D., Meteorology. RALPH S. HOSMER, B.A.S., M.F., Forestry. JAMES G. NEEDHAM, Ph.D., Entomology and Limnology. ROLLINS A. EMERSON, D.Sc, Plant Breeding. HARRY H. LOVE, Ph.D., Plant Breeding. ARTHUR W. GILBERT, Ph.D., Plant Breeding. DONALD REDDICK, Ph.D., Plant Pathology. EDWARD G. MONTGOMERY, M.A., Farm Crops. WILLIAM A. RILEY, Ph.D., Entomology. MERRITT W. HARPER, M.S., Animal Husbandry. JAMES A. BIZZELL, Ph.D., Soil Technology. GLENN W. HERRICK, B.S.A., Economic Entomology. HOWARD W. RILEY, M.E., Farm Mechanics. CYRUS R. CROSBY, A.B., Entomology. HAROLD E. ROSS, M.S.A., Dairy Industry. KARL McK. WIEGAND, Ph.D., Botany. EDWARD A. WHITE, B.S., Floriculture. WILLIAM H. CHANDLER, Ph.D., Pomology. ELMER S. SAVAGE. M.S.A., Ph.D., Animal Husbandry. LEWIS KNUDSON, Ph.D., Plant Physiology. KENNETH C. LIVERMORE. Ph.D., Farm Management. ALVIN C. BEAL, Ph.D., Floriculture. MORTIER F. BARRUS, Ph.D., Plant Pathology. CLYDE H. MYERS, M.S., Ph.D., Plant Breeding. GEORGE W. TAILBY, Jr., B.S.A., Superintendent of Livestock. EDWARD S. GUTHRIE, M.S. in Agr., Ph.D., Dairy Industry. JAMES C. BRADLEY, Ph.D., Entomology. PAUL WORK, B.S., A.B., Vegetable Gardening. JOHN BENTLEY, Jr., B.S., M.F., Forestry. EARL W. BENJAMIN, Ph.D., Poultry Husbandry. EMMONS W. LELAND, B.S.A., Soil Technology. CHARLES T. GREGORY, Ph.D., Plant Pathology. WALTER W. FISK, M.S. in Agr., Dairy Industry. ARTHUR L. THOMPSON, Ph.D., Farm Management. ROBERT MATHESON, Ph.D., Entomology. HORACE M. PICKERILL, B.S. in Agr., Dairy Industry. MORTIMER D. LEONARD, B.S., Entomology. FRANK E. RICE, Ph.D., Agricultural Chemistry. V. B. STEWART, Ph.D., Plant Pathology. IVAN C. JAGGER, M.S. in Agr., Plant Pathology (In cooperation with Rochester University). CHARLES H. HADLEY, B.S., Entomology. DANIEL S. FOX, B.S., Farm Management. WILLIAM I. MYERS, B.S., Farm Management. LEW E. HARVEY, B.S., Farm Management. BRISTOW ADAMS, B.A., Editor. LELA G. GROSS, Assistant Editor. The regular bulletins of the Station are sent free on request to residents of New York State. 422 35701 !' '7i' 7r PREFACE Among the more important insect pests of cultivated plants, and es pecially of fruit trees, are those of the family Coccidae, or scale insects, of which the San Jose scale is an example. An appreciation of this fact led the writer of the reports republished here to make a study of the insects of this family. The investigation was begun in the year 1879, while the writer was Entomologist of the United States Department of Agriculture, and was continued after his retirement from that position, he being then Entomolo gist of the Cornell University Agricultural Experiment Station. Prior to the publication of its results no general work on the scale insects of the United States had appeared, the published accounts of these insects con sisting of isolated descriptions of a few species. In the reports of the results of this study a monographic treatment of the family Coccidae is presented, the previously known American species are redescribed and figured, and forty new species are described. These descriptions are accompanied by detailed figures of the microscopic characters by which the different species are distinguished and which were first elucidated in the course of this investigation. Excepting the catalogue of the Coccidae published by Mrs. Fernald :— in which, however, there are no descriptions of species — these reports remain the only general treatise on scale insects published in the United States. They are, however, unavailable to most workers in economic entomology, as they have been out of print for a long time. Many re quests for them have been received by the New York State College of Agriculture, and so urgent is the demand for this fundamental treatise that it seems wise to reprint the reports. The first of these reports appeared in the Annual Report of the Com missioner of Agriculture for the year 1880 (pages 425 to 500) ; the second, r in the Annual Report of the Commissioner of Agriculture for the years - 1881 and 1882 (pages 501 to 506) ; the third, in the Second Report of the Cornell University Agricultural Experiment Station, published at Ithaca ^ in 1883 (pages 507 to 603). The pagination, and the figure numbers and ^ their sequence, of the original reports have been retained for the benefit of those who will find references to the original works. The regular page numbers of the Cornell bulletin series are also used, however, and these are placed at the top of the page, while the original page numbers, in serted for the benefit of librarians and research workers, are placed at the bottom of the page. Each cut bears below it, in parenthesis, the consecu tive figure number of the Cornell experiment station publication. REPORTS ON SCALE INSECTS J. H. COMSTOCK REPORTS ON SCALE INSECTS (Including descriptions of Coccidae in the collection of the United States Department of Agriculture, with notes upon the habits of those injuri ous to cultivated plants, and the results of experiments in their destruction ) (From Report of U. S. Commissioner of Agriculture, 18S0) INTRODUCTION There is no group of insects, which is of greater interest to horticultur ists to-day than that family which includes the creatures popularly known as " scale insects " and " mealy bugs." There is hardly any shrub or tree but that is subject to their attack; and in certain locali ties extensive orchards have been ruined by them. The minute size of the creatures, the difficulty of destroying them, and their wonderful reproductive powers, all combine to make them the most formidable of the pests of our orchards and ornamental grounds. It is only necessary to cite the mealy bugs of greenhouses, the oyster-shell bark louse of the apple, and the various species of scale insects destructive to citrus fruits to establish this fact. Notwithstanding the great importance of the subject, comparatively little thorough work has been done on the species of this country. This is doubtless in a great part due to the difficulties attending a careful study of even a single species of this group, and the fact that the small size and plain appearance of the insects render them unattractive to most entomologists.* This report on scale insects is an outgrowth of the investigation of insects injurious to orange trees, which was begun last year. In the early part of that investigation I became convinced that by far the greater part of the injury done to orange trees by insects was caused by scale insects; and that I could not do a more useful work than to make an exhaustive study of that family, including not merely those that infest citrus trees, but all the species occurring in the United States. I collected many of our southern species while on a trip ^through the State of Florida during the months of January and February, 188ft; dur ing the following summer I spent three months in the fruit-growing sec tions of California and Utah, investigating the scale insects found there; and extensive collections were also made by assistants and correspond ents in the eastern part of the United States. A series of experiments were made to ascertain the best method of destroying these pests, and with very satisfactory results. These experiments will be continued during the present season. Many species, including all those that in fest oranges in this country, were colonized on small trees growing in pots in the breeding room of the division. In this way we have been able to follow their complete life history. In some instances the species has been observed daily through five generations. For want of time I have been unable to prepare descriptions of all the species which we have collected. I hope, however, to be permitted at some future time to publish a more exhaustive memoir on the subject, and trust that the reader will remember that this is simply the result * Previous to this only about thirty species have been described by American writers ; and of this number more than one-half were deseribed by Dr. Asa Fitch, the first State Entomologist of New York. (276) 426 Bulletin 372 of but little more than one year's study pursued with limited means (there being no special appropriation for it) and in addition to the ordi nary duties of the division of entomology. CHARACTERS OF THE COCCIDAE The scale insects, or bark lice, and the mealy bugs, together with other insects for which there are no popular names, comprise the family known to entomologists as the Coccidae.