LIFE HISTORY AND HABITS. 37 
tended to become foul. The two types last mentioned were about 
equal in efficiency, but the main difficulty lay in the fact that they 
were small and it was easy to overcrowd them. 
The cage used most successfully was a large screen cage of the 
common type, kept outdoors. (See %. 8.) Within the cage were 
several flowerpots, buried to the level of the ground, each containing 
young beet plants. The soil in the pots was kept loose and damp, 
and the soil around the flowerpots was tamped hard. This cage was 
large, well ventilated, and gave the beetles plenty of room in wdiich 
to fly about. Its best feature lay in the fact that the beetles all de- 
posited their eggs in the flowerpots, since this w^as the only place 
where they could bury themselves easily. It this way the eggs w^ere 
concentrated much more than they would have been under natural 
circumstances. As soon as one flowerpot contained a great many 
eggs it could be removed and another substituted. This cage also 
gave natural conditions, as the soil it contained was just as damp as 
that in the field, and since the cage was placed in the sun and was so 
airy the beetles were always kept at the field temperature. The 
death rate was very much lower in this cage than in any of the others 
and there were live adults in it for some time after all had disappeared 
in the other cages. 
DURATION OF LIFE UNDER VARYING CONDITIONS. 
To test the duration of life under varying conditions some adults 
were placed in various styles of cages and others were kept under 
various conditions as concerned the food and water supply. Some 
were kept without either food or water, some with food but ^^dthout 
water, and some with water but ^\dthout food. In every instance 
the beetles lived much longer than was expected of them and proved 
that they are not only quite hardy but can get along on little food. 
One hundred and forty adults were placed in dry battery jars 
without food or water, and the jars were closed with gauze. The 
results were as follows: 
Eighty-two adults died in from 9 to 12 days. 
Forty adults died in from 12 to 14 days. 
Eleven adults died in from 14 to 16 days. 
Five adults died in from 16 to 18 days. 
One adult lived 20 days. 
One adult lived 22 days. 
None of the beetles was very active after the twelfth day. These 
conditions were much more severe than any that they might encoun- 
ter under field conditions. 
The adults kept with water but without food were also kept in 
battery jars. These jars contained about 3 inches of soil, and this 
