584 ANNUAL REPORT SMITHSONIAN INSTITUTION, 1921. 



in nonmalarious regions of Germany, France, and even England, 

 due to the infection of native anopheles by malaria-carrying soldiers 

 returning from the fever-stricken fields of southeastern Europe, in- 

 tensified the importance of the most careful and continued study of 

 insect vectors of disease. 



During the past 20 years the scientific world has thrown itself with 

 ever-increasing activity into the great field opened by the initial 

 discoveries. The greater importance of insect-borne diseases in the 

 Tropics was immediately recognized, and England's great colonial 

 possessions justified, and, in fact, necessitated, the founding of the 

 great Schools of Tropical Medicine at Liverpool and London. A 

 similar school was founded later at Hamburg by the German Govern- 

 ment, but the loss of her tropical possesions has minimized the 

 later work at this institution. Too much praise can hardly be given 

 to the wonderful work done by the Oswaldo Cruz Institute at Rio 

 de Janeiro. The corps of admirable investigators there has been 

 increased from time to time and important discoveries have been 

 made in the lines of medical entomology which the limited space 

 allotted to this article prevents us from considering. 



Medical entomology, however, is only a branch of tropical medi- 

 cine, but it is a branch which absolutely requires the help, not only 

 in investigation but also in teaching, of entomologists. A medical 

 man, a trained pathologist, can hardly, after devoting years of re- 

 search to other lines, become a skilled entomologist, since the field 

 of entomology is so vast that to become skilled in any one of its 

 many aspects requires a lifetime of work. This is coming to be 

 realized. Not only must the taxonomy of insects engaged in the car- 

 riage of disease be critically studied, but their behavior under all 

 possible conditions, their complete biology and ecology, their physi- 

 ology, and many other things must be studied, and the man trained 

 in so-called economic entomology is the one who must be called upon 

 to suggest the best and most economical methods of suppressing these 

 carriers. 



Thus, there have grown up in many of our colleges and universities 

 departments of medical entomology conducted jointly by entomolo- 

 gists and by medical men. At the Harvard Medical College a thor- 

 oughly competent entomologist gives instructions in medical ento- 

 mology. At Cornell University, where there exists one of the strong- 

 est teaching corps of entomologists, especial instruction is given in 

 this direction. The same may be said for the University of Cali- 

 fornia, for the University of Wisconsin, and other institutions. 



And excellent and comprehensive books on the subject of medical 

 entomology have already been published, aside from numerous special 

 books, such as those of the present writer, on mosquitoes and on the 

 house fly, and those of the late Gordon Hewitt and Graham-Smith on 



