ay NORTH AMERICAN FEVER TICK AND OTHER SPECIES. 
from 34° to 53°. With exposure up to 300 hours practically all ticks 
recovered and in most cases deposited viable eggs. In cases of more 
than 300 hours’ exposure practically all ticks survived, but none 
deposited viabie eggs, although in many instances oviposition took 
place. 
In a number of experiments with heat a mean temperature of from 
98° to 102° was maintained. Up to 103 hours of exposure to this 
temperature practically all ticks deposited eggs that were viable. 
With exposure at the same mean temperature of from 144 to 218 
hours’ duration, eggs were deposited, but were found not to be viable. 
They were dry and shriveled when deposited. 
Some of the females survived heating for the longest period, namely, 
218.5 hours. With an exposure of 103.5 hours or more, however, at 
least one-half succumbed. 
EFFECT OF DIRECT SUNLIGHT ON ADULTS. 
~ 
Eleven unengorged females placed in a box exposed to the direct 
rays of the sun in September died in three days. Seven unmatured 
females in direct sunlight from morning until noon seemed dead at, 
noon. They did not survive until the next day, although they were 
removed from the direct sunlight at 2 o’clock. Similar experiments 
showed that death resulted in the case of engorged females after a few 
hours’ exposure to the sun. In experiments with eggs, tubes were 
subjected to direct sunlight for one day. When moistened while 
kept in these tubes, hatching seems to take place normally, and 
hatching followed in similar experiments in which the eggs were 
kept dry. 
EFFECT OF SUBMERGENCE IN WATER ON ENGORGED ADULT 
TICKS. 
Adult ticks have remarkable resistance to the effect of submergence, 
as has been pointed out to be the case with eggs and seed ticks. The 
immediate effect of submergence is to cause a cessation in the activ- 
ity of the ticks, while they become somewhat distended apparently 
from the absorption of water. In August and September, 1905, a 
considerable number of experiments were conducted in which the 
adult ticks were submerged in water from the city mains at Dallas, 
Tex. Judging by the experiments with seed ticks and eggs mentioned 
elsewhere it is not likely that water impregnated with foreign matter 
would have changed the results. During the months mentioned a 
period of submergence of 24 hours did not result in the death of any 
appreciable number of ticks used\in repeated experiments. After 
one or two hours the specimens recovered from the immediate effect 
of submergence and proceeded to deposit eggs which were found to be. 
