2 MISC. PUBLICATION 734, U. S. DEPT. OF AGRICULTURE 



The primary source for the references included was the author 

 card catalog on the Coccoidea that has been developed in the United 

 States Department of Agriculture by various workers during the 

 past 60 years. Preliminary test selections from this catalog, made 

 by several workers on the basis of the two sets of categories out- 

 lined in the preceding paragraphs, showed some diversity of choice. 

 It is therefore possible that the authors have excluded some de- 

 sirable papers and have -included some unnecessary ones in their 

 final selections. The system of presentation used is believed to be 

 sufficiently flexible so that conforming supplementary bibliogra- 

 phies can be issued if needed. 



The form of citation and the abbreviations used are those de- 

 veloped by the library of this Department, as presented in the 

 following publications : 



List of periodicals currently received in the Library of the 

 United States Department of Agriculture. U. S. Dept. Agr. 

 Misc. Pub. 245, 337 p., June 1, 1936. 



Abbreviations used in the Department of Agriculture for 

 titles of publications. U. S. Dept. Agr. Misc. Pub. 337, 278 p., 

 April 1939. 



List of serials currently received in the Library of the 

 United States Department of Agriculture. U. S. Dept. Agr. 

 Bibliog. Bui. 12, 329 p., November 1950. Also Bibliog. Bui. 12, 

 Sup. 1, 218 p., July 1953. 



Bibliographic style. A manual for use in the Division of 

 Bibliography of the Library. U. S. Dept. Agr. Bibliog. Bui. 

 16, 30 p., June 1951. 



It is intended that the author's name plus the year of publication 

 of each individual paper shall serve as a short reference or code 

 designation for the paper. Where two or more papers have been 

 published by an author in one year, alphabet letters in sequence 

 have been added to the dates for the second and following entries 

 to provide the necessary differentiation for each paper. An effort 

 has been made to arrange the multiple publications of any author 

 during a single year in proper chronological sequence and to ascer- 

 tain and use the actual year of publication for each paper. Where 

 this date differs from that on the title page of the volume contain- 

 ing the article, the latter date is shown in parentheses following the 

 abbreviated citation. It is not certain that these efforts have 

 always been successful. Any numbers in parentheses at the end of 

 a citation designate each page within a general article on which 

 some reference to coccids has been found. Except for the few 



