140 JOSEPH HALL BODINE 
B. Methods 
The following general description of methods applies to all 
experiments and any further details will be given in describing 
individual cases. 
All animals were caught in the vicinity of Philadelphia during 
the summer and fall of 1919-1920, brought into the laboratory, 
where they were kept in large screened insect cages, designated 
as stock cages. They remained in these cages for at least a day 
under the usual laboratory conditions, and were fed during this 
time on grass. Inasmuch as grasshoppers normally consume a 
great deal, those kept in the laboratory for a day ate large 
amounts of the grass, and upon examination the alimentary 
canal was found to be filled, thus insuring uniformity as to 
initial amounts of food. General laboratory conditions remained 
constant throughout the experiments, and any slight temperature 
changes, usually occurring at this particular season of the year, 
are noted in data following. 
Annuals were separately weighed in a small covered beaker 
on a rather delicate balance, determinations being made to four 
places of decimals. After weighing they were marked by gluing 
a small numbered tag on the pronotum, which mark could easily 
be removed and again attached, thus avoiding confusion in 
keeping accurate records of individuals. After initial weighing 
they were kept, in groups of five to ten, in small wire insect 
cages. 
In determining water content, individuals were killed with 
chloroform, opened by a longitudinal slit through the abdomen, 
and then put in an oven at 95° to 97°C. and left there for a 
period of one week. This was found to be more than ample 
time for complete desiccation. 
Carbon-dioxide determinations were made by the barium 
hydrate titration method of Lund (7), using single animals, and 
each determination extending over a period of thirty minutes 
to one hour. In suspending individuals in the respiration bottle 
they were carefully tied around the prothorax by means of a 
fine silk thread. This was found to cause them little incon- 
