148 DEPARTMENTAL REPORTS. 



June 30, 1901. This means that in the divisional work, from 1881 to 

 date, 9,441 species of insects have been studied in confinement in an 

 effort to learn their full life histories in order to judge of their 

 economic importance, and if injurious to determine the best point of 

 attack. 



(e) WORK ON THE GEOGRAPHICAL DISTRIBUTION OF THE INJURIOUS 

 INSECTS OF THE UNITED STATES. 



This work has been carried on during the year. A number of 

 maps have been brought down to date and are already found to be 

 most useful in the work of the Division. It is hoped that before long 

 maps of the distribution of the most prominent injurious species will 

 be ready for publication, and so be available to other working 

 entomologists. 



(/) BIBLIOGRAPHIC WORK. 



Part VII of the " Bibliography of the more important contributions 

 to American economic entomology" was published in November, 1900. 

 It brings the bibliography down to January 1, 1900, and completes to 

 that date a work which is unique and of the greatest value to all 

 persons writing upon the subject of injurious insects. 



There was also published in this line, as Bulletin No. 24 (new 

 series) of the Division, a list of works on North American entomol- 

 ogy, compiled for the use of students and other workers, and which 

 includes such titles as those of synopses, catalogues, and lists, 

 arranged under the different groups of insects, thus enabling the 

 worker who wishes to determine species to learn readily just what 

 works to consult. 



(g) PREPARATION OF CIRCULARS OF INFORMATION. 



Many of these useful circulars, which have been of the greatest 

 assistance in the way of reducing the bulk of the correspondence 

 by presenting in concise form the information most frequently asked 

 for by persons seeking remedies for injurious insects, have been 

 reprinted, and three additional numbers have been published during 

 the year. 



(Jl) CORRESPONDENCE. 



The correspondence of the office has been greater than ever before 

 in the history of the Division. About 8,500 letters were written dur- 

 ing the year in answer to inquiries regarding injurious insects, and 

 many others were answered by printed or mimeographed circulars. 



{i) EXHIBIT OF INSECTS AT THE PAN-AMERICAN EXPOSITION. 



Although the space allotted to the Division in the Government 

 building was very small, an instructive exhibit was sent on, compris- 

 ing two parts. The first class, insects injurious to agricultural and 

 horticultural industries in the Northeast, was contained in 28 trays, 

 and comprised specimens of the insects and their work, with enlarged 

 illustrations of those which are too small to be easily made out by the 

 naked eye. Those of the second class were contained in 24 trays, 

 and illustrated very completely the insects which damage forest trees 

 in Northern United States, showing not only the insects themselves, 

 but excellent examples of their work in wood and under bark, as well 

 as on other portions of the trees. 



It is the experience of the Entomologist, and he knows by conversa- 



