FOREWORD 



People having only casual interest in insects usually express amaze- 

 ment 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 prede- 

 cessors, 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 in- 

 formation 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 in- 

 formation 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 coun- 

 tries, 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. 



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