304 ENTOMOLOGY 
body ferms a curved line, the insect presenting a hump-backed 
appearance; in Anopheles the axis forms a_ straight line. 
Culex has short maxillary palpi, while in Anopheles they are 
almost as long as the proboscis. The note of the female 
Anopheles is several tones lower than that of Culer, and only 
the female is bloodthirsty, by the way. As regards eggs, 
larvee and pupee, the two genera differ greatly. The eggs of 
Culex are laid in a mass and those of Anopheles singly; the 
larvee of Culex hang from the surface film of a pool at an 
angle of about forty-five degrees, while those of Anopheles 
are almost parallel with the surface of the water in which 
they live. 
The bite of an Anopheles is not necessarily injurious, of 
course, unless the insect has had recent access to a malarious 
person. Anopheles may be present where there is no malaria. 
On the other hand, it has been found impossible to prove that 
malaria exists where there are no Anopheles mosquitoes. 
Finally, fevers are sometimes diagnosed as malarial which are 
not so. 
Possibly the malarial parasite can complete its cycle c 
l 
os 
— 
development in other animals than man. It is also possible 
that originally the malarial organism was derived by mos- 
quitoes from the stems or other parts of aquatic plants, and 
that its effects on man are incidental phenomena. 
Yellow Fever.—It has now been demonstrated that the 
dreaded disease, yellow fever, 1s transmitted from one human 
being to another by the bite of a mosquito (Stegomyia fas- 
ciata) and in no other way excepting, of course, by the arti- 
ficial injection of diseased blood. The discovery of the mode 
of transmission of the disease was made in Cuba during 1900 
and 1902 by Dr. Reed and his corps of United States army sur- 
geons. These investigators succeeded in transmitting the dis- 
ease to healthy subjects by inoculation from mosquitoes which 
had previously fed on the blood of yellow fever patients. To 
convey the disease, however, a period of ten to thirteen 
days was necessary between the original biting of a patient 
