148 JOSEPH HALL BODINE 
d. Effects of temperature. As pointed out in the preceding 
section, raising the temperature to 38°C. causes marked changes 
in the water content of 'hibernating' individuals. That such 
results can be obtained at other temperatures is shown from a 
series of experiments in which 'hibernating' nymphs were kept 
at 9°, 23°, and 38°C., respectively, for periods of -three weeks 
and fed grass. Progressive increases in the percentage gains of 
water, body weight, and solids take place in all three series, 
being highest, however, at 38°; while with nothing to eat at 
these temperatures the annuals die, thus showing that during the 
winter a real hibernation can hardly be supposed to take place, 
since it is generally understood that hibernating animals require 
no food other than that already stored in the body. 
e. Effects of relative humidity of the air. 'Hibernating' nymphs 
were put into small cages covered with wire gauze and the cages 
were then put into, 1) sealed jars containing wet sand and filter- 
paper, 2) sealed jars with dry sand, and, 3) a desiccator contain- 
ing calcium chloride, and kept at temperatures from 4° to 38°C. 
The animals were not in contact with the sand or wet filter- 
paper, and hence any increase in weight or water content cannot 
be attributed to imbibed water. Nothing was given the animals 
to eat. .Table 4 shows the percentage loss in weight, water, 
and solids for ninety-five individuals treated in such a manner. 
In general it is found that in the jars with dry sand and in 
the desiccators the animals lose weight and water, the losses 
being highest at 38°. Losses in water are relatively higher than 
those in body weight. In the jars with the wet sand, on the 
other hand, marked increases in body weight and water result. 
At 4°C., however, a slight loss in weight (1.4 per cent) is noted, 
but an increase in water of 3.5 per cent takes place. Such a 
slight absorption of water at this lower temperature further 
shows how the organisms are protected during winter, preventing 
freezing and possible destruction. It is evident from these 
results that 'hibernating' nymphs are able to take up water 
directly from the surrounding medium. Breitenbecher (8) finds 
a similar condition in the potato-beetle. It is of interest to note, 
too, that old individuals with low percentages of water are unable 
