We would have been unable to complete this review without the help of many people who have generously given us their time and the benefit of their special experience. We are exceedingly grateful to these individuals for they have contributed much to whatever merit this work possesses; we alone are responsible for the deficiencies and inaccuracies that remain in the text.

Dr. A. B. Gurney, Entomology Research Division, U. S. Department of Agriculture, and J. A. G. Rehn, Academy of Natural Sciences of Philadelphia, have given us much help and advice throughout the preparation of this monograph. Both have patiently answered our many queries, and Mr. Rehn allowed us free access to his large collection of cockroach literature. We are especially pleased to thank them for their many favors.

Many persons have determined at our request the identity of specific organisms. These individuals are cited in the text and to them we extend our thanks. We thank our colleagues, cited in the text, who have made their unpublished observations available to us. We also thank the individuals and organizations for the use of photographs and/or drawings for which they are credited in the accompanying legends.

We thank the following individuals for supplying us with living specimens of the species indicated: T. Campbell, Commonwealth Scientific and Industrial Research Organization, Canberra, New South Wales (Panesthia australis); Dr. L. R. Cleveland, Harvard University (Cryptocercus punctulatus); Dr. N. T. Davis, University of Connecticut (Byrsotria fumigata); Dr. F. Englemann, Albert Einstein Medical School (Gromphadorhina portentosa); Dr. F. A. Lawson, Kansas State College (Comperia merceti); Dr. K. D. Roeder, Tufts University (Hierodula tenuidentata (?)); Dr. E. O. Wilson, Harvard University (Ischnoptera deropeltiformis).

We thank the following individuals for checking the taxonomy of the following organisms or for reading the indicated sections of the manuscript: Fungi.—Dr. R. K. Benjamin, University of California; Dr. E. G. Simmons, Quartermaster Research Laboratories. Protozoa.—Dr. R. R. Kudo, Professor Emeritus, University of Illinois. Helminths.—Mrs. May Belle Chitwood and Dr. J. T. Lucker, U. S. Department of Agriculture. Centipedes and whipscorpions.—Dr. R. E. Crabill, Jr., U. S. National Museum. Scorpions.—Dr. J. L. Cloudsley-Thompson, University of London; Dr. R. E. Crabill, Jr. Spiders.—Dr. B. J. Kaston, University of Connecticut; Dr. R. E. Crabill, Jr. Mites.—Dr. J. H. Camin, Chicago Academy of Sciences; Dr. E. W. Baker, U. S. National Museum. Cockroaches.—Dr. A. B. Gurney and J. A. G. Rehn. Ants.—Dr. W. L. Brown, Jr., Museum of Comparative Zoology, Harvard College. Hymenopterous parasites of cockroach eggs.—Dr. B. D. Burks, U. S. National Museum; Dr. H. K. Townes, University of Michigan. Cockroach-hunting wasps.—Dr. K. V. Krombein, U. S. National Museum. Lepidoptera.—Dr. J. F. G. Clarke, U. S. National Museum; Dr. E. L. Todd, U. S. Department of Agriculture. Miscellaneous insects.—Dr. R. S. Beal, Dr. A. B. Gurney, C. W. Sabrosky, Dr. R. I. Sailer, and J. T. Spilman, U. S. National Museum. Fishes.—Dr. L. P. Schultz, U. S. National Museum. Amphibians and reptiles.—Dr. Doris M. Cochran, U. S. National Museum. Birds.—Dr. Herbert Friedmann, U. S. National Museum. Mammals.—Dr. D. H. Johnson, U. S. National Museum.

We thank the following individuals for reading the entire manuscript: J. A. G. Rehn; Dr. A. B. Gurney; Maj. Gordon Field, U. S. Army; and Dr. H. L. Sweetman, University of Massachusetts. The monograph has profited by the friendly criticism of these entomologists.

We thank Dr. R. A. Howard, Harvard University, for checking lists of plant names; Mrs. Maria E. W. Torok, formerly of the Quartermaster Technical Library, for assistance in obtaining obscure literature; Miss Louise Bercaw, U. S. Department of Agriculture Library, for identifying the journal containing the paper by Vlasov and Miram; the individuals who translated foreign language articles, for which they are credited in the bibliography; and Miss G. Lillian Fede, Quartermaster Research Laboratories, for typing the manuscript.