Distance 'of fliq ht. 



species were found throughout the winter in newly-made breeding 

 places. 



It will be seen, therefore, that none of these four species hi- 

 bernated in the adult form, but A. culici fades was undoubtedly 

 able to tide over the winter by hibernating in the larval form. A. 

 fuliginosus and A. pulcherrimus appeared to be able to pass the 

 winter without any change taking place in their habits. Both 

 adults and larvae of .4. roW so far as it was possible to ascertain 

 by careful search and experiment, seemed to have disappeared 

 entirely during the winter. There are other facts which lend weight 

 to the supposition that A. rossi disappears from the Punjab during 

 the winter, one of which is the recently discovered fact that this 

 species can fly a long distance, and another the fact that it cannot be 

 found in the Punjab until the beginning of July. If adults of this 

 species were present in houses in a hibernating condition during the 

 winter, it is practically certain that they would become aroused from 

 their state of torpor and that the species would become sufficiently 

 prevalent to be easily found in April, when the hot weather begins. 

 It is perhaps not too much to conclude from these facts that at 

 the onset of the winter, A. rossi " migrates"- perhaps by short 

 stages to places further south, and when the summer comes, 

 reappears in the same way. 



DISTANCE OF PLIGHT. 



With regard to this question, also, very few trustworthy obser- 

 vations have been recorded. It is usual to say that the normal 

 distance of flight of " anopheles " does not exceed half a mile. Evi- 

 dence in support of this statement was obtained by the members 

 of the Royal Society's Malaria Commission in India. These 

 observers found that in certain villages in the Central Provinces 

 A. culicifacies, A. stephensi, and A. fuliginosus were always 

 present in abundance if there were extensive breeding places 

 within a quarter of a mile, but that villages, which were distant 

 half a mile from such breeding places, contained few or no " ano- 

 pheles." From this they concluded that the latter distance was 

 beyond the normal flight of these species. In Mian Mir three 

 groups of rain-formed pools afforded an opportunity of making 

 further observations on this point. The first group was 450 

 yards distant from any house, the second 750 yards distance, 



[45 



