116 MOSQUITOES OF NORTH 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 annulatus the male range is through 
i 
— ; the female ——— 
Goeldi, in Brazil, has made an effort to determine the note of the yellow-fever 
mosquito (Aédes 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 (‘ Oberténe’ 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 
