A monograph of the Anopheles mosquitoes of India / by S.P. James and W. Glen Liston.

  • Sydney Price James
Date:
1904
Catalogue details

Licence: In copyright

Credit: A monograph of the Anopheles mosquitoes of India / by S.P. James and W. Glen Liston. Source: Wellcome Collection.

    88/238 (page 66)
    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- A. valence of these two species, at any rate in the Punjab, does not correspond, and that their larvse 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 jeyijoriensis, are placed in different genera (Myzomyia and Pyretophorus). After a consideration of the facts which we have attempted t<j 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 and 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 66]