216 MOSQUITOES OF NORTH AMERICA 



would remain the same, even if the birth rate were to be reduced to zero. In a 

 recent experiment at Mian Mir in India the astounding result was obtained that 

 the mosquito-density was, if anything, increased by the anti-propagation meas- 

 ures — which is equivalent to saying that the population of the United States 

 would be increased by the abolition of the birth-rate. It is to be hoped that if 

 such experiments are to be repeated they will be conducted by observers who 

 have considered the subject. In the meantime, I for one must continue to 

 believe the somewhat self-evident theory that anti-propagation measures must 

 always reduce the mosquito density — even if the results at Havana, Ismailia, 

 Klang, Port Swettenham and other places are not accepted as irrefragable ex- 

 perimental proof of it." 



THE BEHAVIOR OF ANOPHELES TOWARDS CERTAIN COLORS. 



As is pointed out with relation to the yellow-fever mosquito, persons dressed 

 in white are less liable to be bitten than those dressed in black. It was early 

 found that Anopheles, like many other mosquitoes, seeks dark places to rest 

 during the day and alights by preference upon dark objects. A study of the 

 behavior of Anopheles towards different colors has been made by Nuttall and 

 Shipley, which is of sufficient interest to quote in full : 



" The behavior of the insects towards various colours has not as yet received 

 sufficient attention. Whilst engaged with experiments upon the influence of 

 shade and colour we came upon a few data cited in the recent literature. 



" Austen (March 1901, p. 341) writes, ' If the walls of the room be white- 

 washed, with a dark dado, it is interesting to note that the insects will always 

 be found upon the dark strips, and never on the white portions of the wall.' 

 Buchanan (April 1901), in India, notes that ' The men who collect the living 

 Anopheles say that the Anopheles hide in a black coat, but avoid a white coat, so 

 they hang up one or two black coats in the Hospital Ward ' when they desire to 

 catch the imago. Neither Austen nor Buchanan say anything about the influ- 

 ence of colour. The first as far as we know to refer directly to the influence of 

 colour is Joly (May 1901, p. 259) who made observations on mosquitoes in 

 Madagascar. He states, without saying what genus, that mosquitoes there were 

 more attracted to black than to red soil, or to white sand. Persons wearing black 

 shoes and socks were more bitten than when these articles of apparel were white. 

 Brown clothes protected less than those of white or blue. He states that the 

 natives of Madagascar know the attraction black offers to mosquitoes and for this 

 reason hang up a black cloth on the rafters of the room for the insects to collect 

 upon. Joly observed that a yellow haired dog was very much less bitten than a 

 black one. For the same reason the natives are more bitten than the whites, 

 although they suffer less from the after effects. 



" It seemed to us to be a matter of considerable practical utility to determine 

 what influence, if any, colour exerted upon a known malaria-bearing species of 

 mosquito. And we deem our results sufficiently striking to make it worth the 

 while for those who are engaged in similar studies abroad to take the matter up 

 systematically. Our experiments certainly indicate that Anopheles maculi- 

 pennis is attracted by some colours and repelled by others, a matter which would 

 have its practical application in the choice of the colour of clothing and the in- 

 terior of rooms in malarious districts. We are moreover inclined to believe that 

 suitably constructed coloured boxes, or colour-traps, might be of practical utility 

 in and about houses infested with mosquitoes. By periodically closing the boxes 

 and sweeping out the contained insects into a receptacle, or, possibly by render- 

 ing the interior of the boxes sticky a considerable number of mosquitoes might 

 be destroyed. 



