The importance of habits, &c. 



Lastly, it is not difficult to show that Mr. Theobald's method 

 of classification does not bring species which are alike in habits and 

 pathological significance, into the same groups. No two mosquitoes, 

 for example, are more unlike each other than rossi and culicifacies. 

 The former can be recognised at a glance as a typical " anopheles," 

 the latter looks very like a small brown " culex " ; the former breeds 

 exclusively in rain-formed puddles near houses, the latter is one of 

 the typically stream breeding species ; the former, though so abun- 

 dant, is scarcely, if at all, concerned in the spread of malaria, while 

 the latter is perhaps the most active agent in the spread of this 

 disease in India. When we consider further that the seasonal pre- 

 valence of these two species, at any rate in the Punjab, does not 

 correspond, and that their larvae and eggs have entirely different 

 characters, we may well ask ourselves whether a classification 

 is correct which places these two species in the same genus 

 (Myzomyia), while two mosquitoes, which resemble each other so 

 closely in their adult and larval states, in their habits, and in their 

 pathological significance, as listoni and jeyporiensis, are placed 

 in different genera (Myzomyia and Pyretophorus). 



After a consideration of the facts which we have attempted 

 to outline above, we have decided, until further study of ''an- 

 opheles " mosquitoes under natural conditions has been made, to 

 classify these insects only into groups containing closely allied 

 forms. Under each group we have described and illustrated 

 two or more fairly constant types, which we are inclined to 

 regard rather in the light of sub-species or varieties than true 

 species. In defining the groups we have not been guided by any 

 one character (as the scale structure of the adults, for example), but 

 have considered the structure, colour markings, and habits of the 

 adults, the structure arid habits of the larva and pupa, and 

 the general appearances of the eggs. In each group, however, 

 members are met with which partake of some of the characters 

 of one group and of some of another, and these individuals act 

 as the connecting links between the different groups. We believe 

 that the most typical member of each group probably represents 

 a true species, while the other members constitute sub-species 

 or varieties, but whether this is so or not, the arrangement will 

 doubtless simplify matters considerably for medical men in the 



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