32 DEPARTMENTAL REPORTS. 



State experiment stations, and analyses of the material as collected 

 are being made by an assistant in the Division of Chemistry especially 

 detailed for the work. 



Toward the end of this fiscal year the first assistant entomologist 

 undertook a series of experiments with insecticides against the scale- 

 insect enemies of the orange in southern California. This series of 

 experiments extends over into the present fiscal j'ear, and includes 

 spraying of the orchards with a new insecticide known as " distillate" 

 (a kerosene and soap emulsion made with a partiallj^ refined product 

 of the Pacific coast petroleum); also comparative sprayings with the 

 ordinary kerosene emulsion. These experiments were directed against 

 the black scale, the purple scale, and the silver mite. For the silver 

 mite also sprayings were made with a sulphur-lj^e wash, and the latter 

 in combination ^yith kerosene emulsion. Experiments were also made 

 in dusting with dry sulphur trees which had just been sj)ra3'ed with 

 water. Tests were made to determine the relative value of the mechan- 

 ical mixture of kerosene and water (not previously used on citrus trees) 

 and the emulsions named above. 



(c) DETERMINATION OF SPECIMENS SENT IN. 



As reported in previous years, the difi'erent experts in the Division 

 have been obliged to devote considerable time to the naming of speci- 

 mens for experiment station entomologists and others who have not 

 access to large collections either of specimens or of books. This 

 labor, excessive as it is, makes no showing in the practical output of 

 the office. It is indirect work, however, which must be done, and 

 which pays in the long run by facilitating the work of State officials. 



(cZ) GENERAL INVESTIGATIONS OF THE LIFE HISTORIES OF INJURIOUS 



INSECTS. 



During the fiscal year life-history notes were made uj)on G24 species 

 which had not before been studied in the insectary. The catalogue 

 number of the biological series so studied reached 9,284 on June 30, 

 1900. 



(e) WORK ON THE GEOGRAPHIC DISTRIBUTION OF THE INJURIOUS 

 INSECTS OF THE UNITED STATES. 



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

 new localities have been mapped on information received from expert 

 correspondents in different parts of the country or derived from the 

 notebooks of the office force. Several of the more important maps 

 have been brought down to date, and their consultation in the prepa- 

 ration of an account of any single injurious species is now a matter of 

 necessity as well as convenience. 



(/) BIBLIOGRAPHIC WORK. 



The " Bibliographj" of the more important contributions to Amer- 

 ican economic entomology" has been continued, and Part VII is prac- 

 tically ready for i)ublication. 



