VI PREFACE. 



The Tyroglyphidae make up for the paucity of their 

 species by the enormous number of individuals and 

 their wide distribution. Feeding chiefly upon the 

 very articles which man requires to supply his com- 

 monest wants, they are carried with their food 

 practically all over the civilised world ; only a 

 comparatively small number of species have modes 

 of life unsuited to wide distribution. 



Once more my principal thanks for assistance in 

 the investigations recorded in this work are due to 

 my wife, who has shared in all of them ; and whose 

 skilful hand in minute dissection and in microscopical 

 preparation, and in the rearing of minute living Acari, 

 has more or less defied the years which have passed 

 over our heads ; and has often attained success when 

 I should probably have failed without her help. I 

 have also to record my thanks to my late cousin, 

 Mr. M. J. Michael, of the Davos Platz, for unwearied 

 assistance in cutting serial sections of these minute 

 creatures, in which he was remarkably accomplished. 

 I have to record my indebtedness to Mr. E. Bostock, 

 of Tixall, Mr. C. F. George, of Kirton Lindsey, and 

 Mr. F. Enock, for aid in collecting specimens; to 

 Mr. H. Waddington, of Bournemouth, for assistance 

 in obtaining those chemicals upon which some of the 

 Tyroglyphidse like to feed ; to Mr. Sherborne, of the 

 British Museum, for help as to the exact dates of 

 the various parts of some of the more difficult foreign 

 publications which I required for the purposes of 

 completing bibliography or settling priorities; and 

 to almost all the foreign acarologists for the kindness 



