114 MOSQUITOES OF NORTH AMERICA 



Smith, in discussing the question of the food of adult mosquitoes, states that 

 he has examined the stomachs of a number of specimens, and has found some of 

 them filled with a colorless liquid like plant nectar. On the other hand, with 

 Aedes soUicitans, a salt marsh species, he has found the stomach filled by a mass 

 which he could not distinguish from thin marsh mud. 



Some very interesting observations have been made upon biting of corpses by 

 mosquitoes. In our section on yellow fever we have given an account of experi- 

 ments made with captive Aedes caloptis at Vera Cruz. In these it was shown 

 that one female feeding upon a corpse twelve hours after death apparently ob- 

 tained blood, but this was only one of a number ; three of a number in another 

 case, one-half hour after the death of the patient, succeeded in feeding with 

 blood. Christy, in making a post-mortem examination in Nigeria, found a num- 

 ber of a large brown Anopheles feeding upon the body of a non-commissioned 

 officer who had died three and a half hours previously. 



The laboratory studies consequent upon the discovery of the relations between 

 mosquitoes and certain diseases have brought about necessary experimentation 

 as to the kinds of food upon which to prolong the life of blood-sucking mos- 

 quitoes used for experimental purposes, and it has been found that they will live 

 almost for indefinite periods upon a vegetable diet, bananas, dates, raisin-grapes, 

 and other fruit used for this purpose, and it has been found that frequent meals 

 of water are necessitated in order to prolong life. One of us (Dyar) has reared 

 two successive generations of Aedes atropalpus in captivity by feeding the adults 

 upon sugar and water. 



MOSQUITO SONGS AND THEIR POWER OF HEARING. 



Probably owing to an association of ideas, the curious sound made by mos- 

 quitoes as they approach one's ear is to most people extremely irritating. This 

 faint sound will waken many from the soundest sleep. It is not loud, and in 

 quality may perhaps best be compared to the distant note of a bagpipe. 



As with flies and other dipterous insects the sounds emitted by mosquitoes 

 are not a true voice. It has been supposed that the sounds are produced in two 

 ways, by the vibration of the wings and by air forced through the thoracic 

 stigmata. Landois, in his classical paper on the sound-producing organs of 

 insects, apparently proved the latter to be the case, but more recent investiga- 

 tions show that he was at fault in his conclusion that the stigmata emit sound. 



Landois thought that mosquitoes produce sounds in two ways. The normal 

 tone, which can not be modified in any way by the insect, is produced by the 

 wing stroke. The common Culex pipiens during flight produces the sound 



(^ ° == {d'). If one removes the wings, head, and all the legs of such a 



mosquito she emits a sound which is much higher than that produced in flight. 

 This sound Landois thought to be produced by the stigmata of the thorax and 

 said it might be called the voice of the mosquito. He found within the spiracle, 

 a membrane, stretched like a double curtain, which he supposed produced the 

 sound when the air was forced through it. He considered the posterior thoracic 



