116 MOSQUITOES OF XORTH AMERICA 



The exact musical note of the different species of mosquitoes seems to have 

 been investigated only in a few cases. Marked differences have been found in 

 the notes of different species. Both sexes emit a sound but there is a marked 

 difference, the note of the males being much higher than that of the female. 

 There is also a slight difference in the note of fed and unfed individuals of the 

 same species. 



Landois found that in Culiseta annulatiis the male range is through 



K— ^ ~^ ; the female \ i) o a g 



Goeldi, in Brazil, has made an effort to determine the note of the yellow-fever 

 mosquito (Aedes calopus). It has several times been stated by observers that 

 this mosquito makes no sound when it flies, but this Goeldi denies. Aided by 

 two of his Museum colleagues who were musicians, he made his experiments as 

 follows : 



" For this purpose we made use of the inhabitants of two cages, one contain- 

 ing only males ; the other only females. An hour of the afternoon was selected, 

 and the cages exposed to the mild rays of a partly cloudy day. We made use of 

 a zither and of a tuning fork of a known number of vibrations. We found that 

 the pitch of the female corresponded to C while that of the male corresponded to 

 A. The two sounds hold the relation of a sixth to each other ; the A of the male 

 corresponds to 880 vibrations ; the C of the female to 480 vibrations. In each 

 case we had the impression that along with the principal sound there was heard, 

 from time to time, the respective octaves so that the timbre seemed to be covered 

 by the proper concomitant sounds (' Obertone ' in German technico-acoustic 

 language). It is evident that a certain effect is produced upon the pitch of the 

 sound by the greater or less dilation of the abdomen with food, and who knows 

 whether not also under the psychic effect of the influence of mutual suggestion." 



The musical note of Anopheles has been studied by Nuttall and Shipley and 

 their results will be found in our section on malaria in a later part of this 

 volume (p. 211). 



The curious reaction of a swarm of mosquitoes to sound of a certain pitch 

 was related to Osten Sacken by a Cuban naturalist. While a swarm of mos- 

 quitoes was hovering over the head of the observer a band was playing at a dis- 

 tance. Whenever the note A was struck the mosquitoes were all precipitated 

 downward, striking against the face of the observer. The following observation 

 along the same line is from Howard's " Mosquitoes." 



" Mr. A. DeP. Weaver, an electrical engineer of Jackson, Miss., wrote me 

 that while engaged in some experiments in harmonic telegraphy, in which a 

 musical note of a certain pitch was produced by electrical means, he was amazed 

 to find that when the note was raised to a certain number of vibrations per 

 second, all mosquitoes, not only in the room where the apparatus was, but also 

 from other parts and from outside, would congregate near the apparatus and 

 would be precipitated from the air with astonishing force, striking their bodies 

 against the apparatus. He states that he therefore covered a large surface with 

 sticky fly-paper and after sounding the note for a few second captured all the 

 mosquitoes in the vicinity. He then devised an apparatus to electrocute them. 

 A section of wire window screen with the paint removed was mounted on a board 

 and small pins were driven between the meshes, the heads coming flush with the 



