160 



Hunter (S. J.)- The Sandfly and Pellagra. III. — Jl. Econ. Entom., 

 Concord, vii, no. 3, June 1914, pp. 293-294. 



This is the author's third report on the entomological aspects of the 

 causes of pellagra, and includes studies on the biting habits and mor- 

 phology of the mouth-parts of Simulium vitaUum. In experiments 

 conducted in southern Montana, near the Madison River, it was found 

 that the fly was active on cool days when the temperature was below 

 70°. The bite was not always immediately noticeable, and it seems 

 probable that the fly attaches itself to its host by means of its mouth 

 parts, since it is not readily detached when it has once settled down to 

 feed. A monkey used during 1912 for inoculations from sandflies, 

 and inoculated on 22nd December 1912, began to exliibit in November 

 1913, a marked stomatitis, accompanied by diarrhoea ; it continued 

 to lose in weight, and the colour of the face changed to a pale ashy gi'ey. 

 The author admits that the report does not at present warrant any 

 conclusions for or against the theory that pellagra is carried by 

 Simulium. 



Howard (L. 0.). The Yellow-Fever Mosquito. — U.S. Dept. Agric, 

 Washington, D.C., Farmers' Bull. no. 547, July 1913, pp. 1-16, 

 6 figs. 



This is a popular account of Stegomyia fasciata, F., and its relations 

 with yellow fever. This mosquito is inseparably associated with man 

 in the tropics and is essentially a town species, never found normally 

 at great distances from habitations. A female will bite within 18-24 

 hours after emergence, and is recorded to have sucked blood 18 times 

 in 31 davs. Young, healthy individuals are more hable to be attacked 

 than older ones, and white races than black. The mosquitos are most 

 active in the early morning at sunrise, and on dull cloudy days ; they 

 do not bite in the sunlight or in the open. As a rule the adult does 

 not hve longer than 40 days, though a female has been kept alive for 

 154 days and a male for 72 days. The mosquito can transmit yellov/ 

 fever 12 days after it becomes infected, and can probably do 

 so throughout its hfe ; it is very sensitive to differences of 

 temperature, and displays its greatest activity at about 82°. There 

 is no positive evidence that vessels anchored more than half a mile 

 from shore will be visited by these mosquitos under natural conditions, 

 but they may be carried great distances on ships, etc., and have been 

 found in New York on vessels coming from Vera Cruz, and are carried 

 frequently by trains from New Orleans and other southern cities to 

 Baltimore, New York and other cities in the northern States. 



The eggs are laid in one or more lots, and may remain dry for long 

 periods, hatching when they reach water. S. fasciata breeds almost 

 exclusively in artificial receptacles, such as gutters, discarded bottles, 

 tins, etc. The incubation period is two days. The larval stage lasts 

 for six days at least, and the larvae can resist a considerable sahnity 

 in the water and can also live out of water for some time if the surround- 

 ings be moist. The pupae are also very resistant to drying. The 

 pupal stage occupies upwards of 36 hours, and the average Ufe-cycle 

 from 11-18 days. 



The spread of yellow fever can be most effectually controlled by 

 measures directed against the mosquitos and the protection of infected 

 persons against their bites. 



