12 BULLETIN 780, U. S. DEPARTMENT OF AGRICULTURE. 
RACE. 
In experiments recorded in the present paper the bees used have 
been largely hybrids, being for the most part grade Italians. Two 
each of tested Carniolans and Caucasians and a few common blacks 
hare been among the colonies used. The bees were found to be sus- 
ceptible to Nosema infection in all instances. It is not unlikely that 
future studies will show a difference among the races as to their 
relative immunity to the disease, but sufficient data are vet wanting 
to justify a definite statement in regard to the point. 
Nosema infection has been reported from Australia (Price and 
Beuhne, 1910), Brazil (Zander, 1911), Canada (White, 1914), Eng- 
land (Fantham and Porter, 1911), Germany (Zander, 1909), and 
Switzerland (Nussbaumer, 1912). Studies have not yet been made in 
Denmark on the disease (Bahr, 1916). The writer (1914) has found 
it in samples of bees received from 27 different States of the United 
States. Out of 120 samples examined 40 contained the parasite. 
Samples showing infection were received from the coast plains and 
mountains of the East, from the plains of the Mississippi Valley, 
from the plateaus and plains of the West, and from the South and 
the North. 
The infection was found in bees received from Florida and southern 
California, but in 15 samples received from Texas it was not found. 
The data thus far obtained indicate that less infection occurs in the 
southern portion of the United States than farther north. Whether 
it is found in the Tropics or in the coldest climate in which bees are 
kept is not yet known. 
Laidlow (1911) reports that heavier infection was encountered in 
some parts of Australia than in others. Xussbaumer (1912) reported 
the infection from 14 of the cantons of Switzerland. 
The practical import of these observations in connection with the 
climate, to the beekeepers of the United States at least, is that the 
presence of the disease in a region can not be attributed entirely to 
the climatic conditions present. It is possible, however, that the 
climate of a particular region may affect somewhat the occurrence 
and the course of the disease in that locality. 
Infection in apiaries has been found to occur at all seasons of the 
year, but is greatest during the spring. In the studies reported in 
the present paper (p. 20) infection was greatest in April and May, 
being greater in these months than in March. Very little of a 
definite character is known of the infection as it occurs in nature 
during the winter. Experimentally it has been found that bees are 
susceptible to infection with Nosema apis at all seasons of the year. 
