CITY OF WASHINGTON PUBLISHED BY THE SMITHSONIAN INSTITUTION DECEMBER 2, 1960 THE LORD BALTIMORE PRESS, INC. BALTIMORE, MD., U. S. A. FOREWORD People having only casual interest in insects usually express amazement when they learn how much is known about this most numerous group of animals. However, while entomologists have good reason to take pride in the accomplishments of their contemporaries and predecessors, they are more likely to be appalled by how much remains to be learned. We are indeed ignorant of even the identity of fully half and probably much more than half the total number of insect species. Of those that have been described, we have reasonably complete information about the behavior and basic environmental relationships for only a comparative few. The great majority of the remainder are known only from specimens found in museum collections. Such information as we have about these species usually amounts to no more than date and locality of collection. This is true of the cockroaches, which now include approximately 3,500 described species. Conservative estimates based on partially studied museum collections and the percent of new species found in recent acquisitions, particularly from tropical and subtropical countries, indicate that at least 4,000 species remain unnamed. Although the group is well known in general terms to nearly all entomologists, there is an almost complete void of information about all except the few domestic species and, to a progressively diminishing degree, some 400 others. Many details about the lives of even those that share man's habitations are not fully understood. This then is a rough measure of how little is known about cockroaches. With the exception of mosquitoes and a few other comparatively small groups of insects on which work has been concentrated, it is doubtful if any other comparable segment of the world's insect fauna is better known. Already an estimated 800,000 kinds of insects have been described, and since this figure is generally regarded as less than half the actual total, think what this means in terms of knowledge yet to be assembled. No wonder entomology is a growing science with a promising future, but the magnitude of the task also presents a serious obstacle to progress. Progress can continue only if the scattered literature resulting from the diversified labors of hundreds of contributors is brought together and summarized in thorough and well-organized compilations that can serve as a solid basis for future research.