32 NORTH AMERICAN FEVEB TICK AND OTHER BPECEES. 
from.')! to 53 . With exposure up to 300 hours practically all ticks 
recovered and in mosi cases deposited viable eggs. In cases of more 
than 300 boms' exposure practically all ticks survived, but none 
deposited viable eggs, although in many instances oviposition took 
plac< . 
In a number of experiments with heal a mean temperature of from 
98 i" L02 was maintained. Up to in. - ; hours of exposure to this 
temperature practically all tick- deposited eggs thai were viable. 
Willi expo-iire at the same mean temperature of from 144 to 218 
hour.-' 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 longesl period, namely. 
2 L8.5 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 day-. 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 
-bowed 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 o'i 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 Augu-I and September, 1905, a 
considerable number of experiment- were conducted in which the 
adult tick- were submerged in water from the city main- at Dallas, 
Tex. Judging by the experiment- with seed ticks and egg- mentioned 
elsewhere it i- not likely thai water impregnated with foreign matter 
would have changed the results. During the months mentioned a 
period of submergence of 24 hours did not resull in the death of any 
appreciable number of ticks used in repeated experiment-. After 
"lie or t\\<» hour- the specimens recovered from the immediate effect 
of submergence and proceeded to depo-it eggs which were found to be 
