THE ACARINA OR MITES.' 



By Nathan Banks, 

 Entomological Assistant, Bureau of Entomology. 



PREFACE. 



The mites have always attracted considerable interest, both from their minute 

 size and because of the remarkable habits of some species. Although many persons 

 have examined them in a desultory way, but few have really studied them. Con- 

 sequently there is a great amount of literature, much of which is not reliable. Too 

 often entomologists have considered that their knowledge of insects in general was a 

 sufficient basis for the description of mites. Probably the lack of general works on 

 mites has been responsible for many errors. For years the only work treating of the 

 mites as a whole that has been accessible to American naturalists is Andrew Murray's 

 Economic Entomology; Aptera (1877). In this book nearly 300 pages are devoted 

 to Acarina. Unfortunately Mun'ay's treatment is far from satisfactory and abundantly 

 stored with mistakes, many, however, taken from other writers. 



Since that book was published several European specialists have been at work on 

 the European fauna and produced monographs which are of great accuracy. Not 

 only have various new facts been discovered, but many of the old facts have been 

 given quite new interpretations. Such a belief as the parasitism of the Uropoda on 

 the Colorado potato-beetle seems hardly as yet to have been eradicated. To present 

 a reliable text to the American reader is my intention. Very frequently I have 

 obtained facts of importance and interest from the European literature. Particularly 

 is this true with those parasitic groups with which I am not so well acquainted. 

 Errors will of course be found, but great care has been exercised in choosing the 

 sources of information. 



I have given tables to all the known American genera, and in some families added 

 other well-known genera which will doubtless occur in our fauna when it is more 

 thoroughly explored. 



Practically the only door through which one may enter into the systematic study 

 of mites in general is Canestrini's Prospetto dell' Acarofauna Italiana, but for certain 

 families there are other works, which will be found listed in the bibliography. 



INTRODUCTION. 



The acarians form an order in the great class Arachnida. They are thus related to 

 spiders, daddy-long-legs, and scorpions. A few writers at various times have claimed 

 that the mites were a separate class, but the best sense of modern authors is that they 

 are genuine arachnids, and in many ways closely related to solpugids and phalangids. 

 Dug^ was the first to see their relation to phalangids, a view which is now generally 

 held by acarologists. Duges divided all arachnids into two subclasses: Hologastra for 



^ In 1904 there was published in the Proceedings of the U. S. National Museum a work 

 entitled "A Treatise on the Acarina or Mites." In the practical absence of available 

 information on mites it was found especially useful to economic entomologists and 

 teachers. As it has long been out of print and the demand for it continues, the author 

 has revised and enlarged the original work, bringing it up to date and adding many new 

 Illustrations, so that this is better considered a separate work. 



