PREFACE. V 



Cams' "Handbuch der Zoologie." In the succession of the 

 families of the Acarina, the suggestions of Claparede, in his 

 "Studien der Acariden," have been followed, and in the 

 preparation of the general account of the Arachnids the 

 writer is greatly indebted to Claparede's elaborate work on 

 the " Evolution of Spiders." 



In the preparation of this "Guide" the author has con- 

 sulted and freely used IVestwood's invaluable "Introduction 

 to the Modern Classification of Insects ; " Gerstaecker's 

 " Arthropoden" in Peters and Cams' "Handbuch der Zoo- 

 logic;" Siebold's "Anatomy of the Invertebrates" (Burnett's 

 translation, 1854) ; Newport's Article "Insecta" in Todd's 

 Cyclopaedia of Anatomy and Physiology ; and Dr. T. W. 

 Harris' "Treatise on Insects injurious to Vegetation." He 

 would also acknowledge his indebtedness to Professor L. 

 Agassiz for many of the general ideas, acquired while the 

 author was a student in the Museum of Comparative Zoo- 

 logy at Cambridge, regarding the arrangement of the orders 

 and classes, and the morphology of the Articulates. 



For kind assistance rendered in preparing this book, the 

 author is specially indebted to Baron R. von Osten Sacken, 

 who kindly read the proof sheets of the chapter on Diptera ; 

 to Mr. F. G. Sanborn for the communication of many speci- 

 mens and facts ; and also to Messrs. Edward Norton, S. H. 

 Scudder, J. II. Emerton, C. T. Robinson, A. R. Grote, G. D. 

 Smith, E. T. Cresson, P. R. Uhler, C. V. Riley, Dr. J. L. Le- 

 conte, Dr. Hagen, "W. C. Fish, and E. S. Morse. For much 

 kind assistance and very many favors and suggestions, and 

 constant sympathy and encouragement during the printing 

 of the work, he is under special obligation to his valued 

 friend, Mr. F. W. Putnam. The types of the new species 

 noticed here are deposited in the Museum of the Peabody 

 Academy of Science. He would also express his thanks to 



