LIFE HISTORY 
35 
Summary of Duration of Life Round 
In summarizing - the duration of the life round, we 
find that the writer’s Washington observations made 
the total life round approximately ten days, as indi¬ 
cated in an earlier paragraph. These were midsummer 
observations made in August, 1895, on the Depart¬ 
ment of Agriculture grounds in the city of Washing¬ 
ton, but in a warmer climate they may be hastened 
even beyond this minimum. Thus, in India Surgeon 
Major F. Smith, of the Royal Army Medical Corps, 
found at Benares that from a collection of one day’s 
fresh droppings of three horses the adult Musca domes- 
tica was obtained on the eighth day after the laying of 
the eggs, thus shortening the period considerably. 
Moreover, Doctor Hewitt’s minimum rate of growth 
was: egg, eight hours; first-stage larva, twenty hours; 
second-stage larva, twenty-four hours; third-stage 
larva, three days; pupa, three days—a total of eight 
days and four hours, surely a much shorter period 
than often happens in England, although the occa¬ 
sionally high summer temperature combined with the 
moist climate of that country may occasionally bring 
about this shortening. Mr. Newstead’s observations 
in Liverpool, on the other hand, show a minimum 
period of from ten to fourteen days and a maximum 
of from four to five weeks or longer. 
Dr. A. Griffith, Medical Officer of Hove, England 
(a seaport on the English Channel), experimented with 
house flies during 1904-7. He gives as the minimum 
