PREFACE 



IN THE past few years there has been a growing demand for an ele- 

 mentary and comprehensive work on mites, both from the pro- 

 fessional acarologist and from students and investigators in related 

 fields such as entomology, zoology, and parasitology. In the United 

 States before 1940 there were only a few scattered workers in the 

 field. Now, the interest created by the recognition of mites that carry 

 human diseases and the problems created in agriculture by the use of 

 DDT which causes heretofore unknown and undescribed species to 

 become serious pests of plants have resulted in a growing list of both 

 students and professional workers who have become interested in 

 learning something about the Acarina. It is for these people that this 

 book has been written. 



The German acarologist, Vitzthum, completed the section on Acari 

 in Bronns' "Klassen und Ordnungen des Tierreichs" in 1942. While 

 this work is comprehensive it is also exhaustive and does not present a 

 digest of available knowledge for the beginner. Vitzthum's masterpiece 

 has been extremely helpful to us, and we have followed his classifica- 

 tion except in cases where our studies have indicated necessary changes. 

 One of the most apparent deficiencies of Vitzthum's monograph for 

 the beginner is its complete lack of keys and the absence of discussion 

 of the Acarina family by family. 



The present book consists of a short introduction to the general 

 structure, development, and ecology of mites in general and then each 

 family is considered as a unit. We have prepared keys to the group that 

 are designed to enable the reader to place any acarine in its proper 

 family. In the discussion of each family the following information is 

 given if it is known: a diagnosis, a list of genera and their type species 

 (the reader is referred to S. A. Neave, 1939, "Nomenclator Zoologicus," 



vii 



