VI PREFACE 



sion to be allowed to copy them and, when these requests have been 

 denied have urged that "the material might be printed and made 

 available for the use of all. For this reason the accumulated 

 materials have been again revised and extended and are offered 

 on the following pages. 



The number of separate publications or papers dealing with 

 the family Coccidae is legion. Mrs. M. E. Fernald prepared a 

 catalogue which gives references to the literature dealing with all 

 the species. This catalogue is of inestimable value to every 

 student of the Coccidae. The numerous titles to papers have not 

 been accumulated thus far by any one and I have given a consider- 

 able list of the books and papers dealing with the family. No 

 attempt has been made to make it complete. 



The fact that no figures are included in this volume may 

 appear to many as an error. The tables were prepared primarily 

 for the use of students. Those who have had any experience in 

 teaching know that most students will not undertake anything 

 they are not forced to do. The omission of figures makes it neces- 

 sary for them to study their specimens rather than figures. 



A careful examination of the figures and descriptions of the 

 species of Diaspidinae has made it possible to refer a considerable 

 number of the species to the generic groups recognized in this 

 volume. A number of species, however, either from the meagerness 

 of their descriptions or the imperfections of their figures, have 

 been included under the generic group where they were originally 

 described. Further investigation will show that some of these 

 species are misplaced. 



The materials accumulated are from such varied sources, that it 

 is impossible to name all the authors. I take this opportunity to 

 acknowledge my indebtedness to all students of the Coccidae for 

 the material that I have culled from their writings. The following 

 are deserving of special mention : Berlese, Cockerell, Comstock, 

 Green, Hempel, Kuwana, Leonardi, Marlatt, Maskell, Newstead, 

 and Signoret. I am also greatly indebted to all my former students 

 of the Coccidae for many suggestions and criticisms of the form and 

 arrangement of the various tables and of the characterizations used 

 therein. 



A. D. M. 



UNIVERSITY OF ILLINOIS, 



URBANA, ILLINOIS, 



July 15, 1920. 



