1904.] L. Rogers — Special Report on Fever in Dinajpur Disi. 49 



actually caught in the houses. That which was by far the most com- 

 monly met was A. Fuliginosus, as will be seen from the table below. 

 Next came A. Rossii, although this variety was only present in large 

 numbers in the houses near the tanks in the centre of the town. The 

 next most frequently met with was A. Listoni, and this is probably the 

 most important of all, for the Malaria Commission^ found it to be 

 associated with a very high prevalence of malaria in the Duars, where 

 it was the most common anopheles met with and the only one which 

 they found to be naturally infected. It has not hitherto been found 

 south of the Jalpaiguri district as far as I know, so its presence 

 throughout all the most malarious parts of Dinajpur is noteworthy, for 

 although only found in small numbers during my visit from January 

 to March, yet there are good reasons for believing that it may be 

 present in much larger numbers in the rainy fever season. In the first 

 place this variety breeds exclusively in running water, so that its breed- 

 ing-places in the cold dry season are limited to the streams on either 

 side of the town. In the rainy season, however, there will be nume- 

 rous flowing streams and earth-lined drains which will afford it adequate 

 breeding-grounds throughout the town. Once more in the Punjab 

 Major Adie^ has shown that although in the dry season A. Fuligi- 

 nosus is the common anopholes met with, yet in the rainy fever 

 season it is nearly entirely replaced by the A. Culicifacies, which 

 belongs to the same group of small dark malaria carrying mosquitoes 

 as does the A. Listoni met with in Dinajpur. It is probable, then, that 

 this dangerous variety is much more common in the fever than it is in 

 the dry season. The other two varieties met with in the houses are 

 of much less importance, for they belong to the wild group, which 

 breed in swampy places and rarely enter inhabited houses, while they 

 have never yet been found to be carrying malaria under natural condi- 

 tions. These are the A. Barbirostris and A. Sinensis, the latter having 

 only once been found in the houses, although their larvae were met with 

 not very rarely in weed-grown streams and canals, especially to the 

 east of Dinajpur. 



With regard to the breeding-places of these varieties, it may be said 

 that A. Fuliginosus was met with in both the streams and also in weed- 

 grown tanks. A. Rossii in the tanks most commonly, A. Listoni 

 chiefly in the sandy river to the west of the town, especially close to 

 the grassy banks, but they must also have been breeding in the more 

 sluggish stream to the east, as they were caught in the houses of that 

 part of the town. The other two were found in the weedy streams as 



1 Reports of the Malaria Commiesion of the Royal Society. 

 * Adie, Indian Medical Qatette, 1903. 

 J. II. 7 



