ing the species. Much information obtained by the earlier investi- 

 gators of the Division of Entomology, Dr. L. O. Howard, Mr. C. L. 

 Marlatt, Mr. C. II. T. Townsend, and Mr. E. A. Schwarz, has been 

 used. On account of the painstaking character of the work of Mr. 

 Schwarz, and his intimate knowledge of related species, his reports, 

 largely unpublished, have been found especially valuable. In pre- 

 senting this work the authors have taken care to state fully the data 

 furnishing the basis for the various conclusions. Under each impor- 

 tant heading will be found, first, a description of the methods and 

 apparatus employed; second, a full and in many cases tabular state- 

 ment of observations; third, the obvious conclusions. Care has con- 

 stantly been exercised to avoid errors likely to result from artificial 

 conditions in the laboratory. A large part of the work of the past 

 year was in ascertaining how closely laboratory results corresponded 

 to the actual conditions in the field. The writers have on many occa- 

 sions been surprised to discover how close the correspondence is, and 

 consider that the demonstration on a large scale of the possibility of 

 accurately determining the details of the life history and habits of an 

 insect by laboratory investigations is by no means the least important 

 of the results of the investigation. 



The laboratory work which has led to this paper was planned origi- 

 nally by the senior author, who has also supervised the later develop- 

 ments of it. However, practically all the labor of conducting the 

 experiments and observations has devolved upon the junior author, 

 who has suggested from time to time many important modifications of 

 the original plan. Specifically, all of the bulletin except the first por- 

 tion, dealing with historical matters, the destructiveness of the pest, 

 and the prospects, and the last portion, dealing with methods of com- 

 bating it, was written by the junior author, although revised in some 

 particulars after it had been submitted by him. The illustrations 

 used are from photographs taken for this work by the junior author, 

 with the exception of the text figures and the illustrations of insects 

 often mistaken for the boll weevil, of which those marked "original" 

 are, with one exception, from drawings prepared by Miss L. L. How- 

 enstein, one of the artists of the Division of Entomology. 



