Difficulty of assigning specimens to their correct genera. 



indicates that Mr. Theobald is himself somewhat uncertain about 

 the matter. Colonel Giles gives an instance of a species which 

 formerly figured as the type-species of a genus, but which has now 

 been relegated to a humble position in quite another genus, and we 

 have ourselves sent home specimens of A. stephensi which, on one 

 occasion, were identified by Mr. Theobald as belonging to the genus 

 Nyssorhynchus and on another to the genus Cellia. If the author 

 of a classification finds it difficult to place specimens in their correct 

 genera it is scarcely to be expected that the medical man in the 

 tropics will be able to do so, and, as a matter of fact, the method 

 which most workers in the tropics and, so far as we have been 

 able to ascertain, most entomologists who desire to follow Mr. 

 Theobald's classification of "anopheles" adopt, is first to ascertain 

 the specific name of the specimen and then to refer to Mr. Theobald's 

 synoptic table for the generic name. This shows that the differ- 

 ences between the different species are more marked and more 

 easily found out than are the differences between the various 

 genera a fact which is opposed to all the principles of classifica- 

 tion. In view of these difficulties we are somewhat surprised to 

 see that authors who have recently written upon methods for 

 the study of tropical diseases, have adopted without question the 

 many new genera which Mr. Theobald has created ; but we 

 find some consolation in thinking that in doing so they have 

 been influenced rather by the fear lest their books may not be con- 

 sidered up-to-date than by their own personal opinions on the 

 matter. In the preface to the second edition of his book on 

 mosquitoes, Colonel Giles frankly admits that he has followed 

 implicitly Mr. Theobald's monograph, and says : " It must be 

 understood that I merely reproduce, and desire to imply no 

 personal opinion as to the justness or otherwise of the conclusions 

 involved." Drs. Stephens and Christophers in their book on 

 the practical study of malaria, and Dr. Daniels in his book 

 entitled " Laboratory Studies in Tropical Medicine," have also 

 merely reproduced Mr. Theobald's synoptic table of the Ano- 

 phelina, and have not attempted to explain how the different 

 o-enera under which these insects are placed may be distin- 

 guished from one another by anyone who has not the type-insects 

 before him. 



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