THE HOUSE FLY 45 



mitting this disease, it remained for Dr. Patrick Manson, of London, 

 to point out in 1895 that the malarial parasite had an alternate mode 

 of generation, and he considered some blood-sucking insect (probably 

 a mosquito) as the most probable host. His pupil, Dr. Ronald Eoss, 

 an English military surgeon, soon went to India, and after patiently 

 dissecting the bodies of hundreds of mosquitoes, finally discovered one 

 having pigmented bodies in the stomach after biting a malarial patient. 

 In 1900, Sambon and Low, and Grassi, conducted in the most malari- 

 ous sections of Italy careful experiments which proved to the world 

 that malaria is transmitted to man through the bites of the malarial 

 mosquito, Anopheles maeulipennis. These experiments have since 

 been duplicated and the results confirmed by many others in different 

 parts of the world. 



Mosquitoes breed only in water,- and the malarial mosquito will 

 breed in almost any pool where other kinds flourish, but is never so 

 abundant as the rain-barrel mosquito, Culex pipiens, or the salt-marsh 

 mosquito, Culex sollicitans. It lays its eggs singly on the surface of 

 the water. They hatch in a few hours, and the young larva? or wigglers 

 feed in the water on minute particles of vegetable matter. Each larva 

 goes to the surface every few minutes to inhale air through the tube or 

 siphon near the tail. In a few days the wiggler changes to a peculiar 

 hunchback pupa, and the adult mosquito emerges two or three days 

 later. Only a week is required in warm weather to complete the life 

 cycle. 



As a rule, mosquitoes do not fly far, and usually breed in the vicin- 

 ity where they occur. The salt marsh mosquito is an exception to 

 this rule, and often flies inland for twenty-five or thirty miles, though 

 it breeds only near the coast. 



From the records of the State Board of Health it appears that for 

 the decade ending with 1903, 1,073 deaths, or more than 100 each 

 year, occurred in Connecticut from malarial diseases alone. Dr. 

 Howard obtained similar figures from those states where statistics are 

 kept (less than one half of the states keeping them, and these being in 

 the north), which show that more than 12,000 deaths occurred in 

 eight years from malaria. From the records of a number of cities it 

 appears that two deaths occur from malaria in the south to one in the 

 north, and on this basis and including the non-registration states, he 

 concludes that the annual death rate from malaria in the United 

 States must amount to 12,000, and that it would be 96,000 for the 

 eight-year period. 14 



But with malaria perhaps more than with any other disease the 

 death rate is a small indication of the economic loss suffered. Many 



14 L. O. Howard, ' ' Economic Loss to the People of the United States through 

 Insects that Carry Disease." Bureau Entomology, Bull. 78, p. 10. 



