354 Trans. Acad, Sci. of St. Louis 
her mouthful of dirt was always dry. Odynerus geminus 
was lavish in the use of water, when mouthful by mouth- 
ful she bit away the chimney over her nest, but this eco- 
nomical little creature either bit away every particle that 
contained water or bit out the dry dirt and disgorged 
upon it just enough water to make it of the right con- 
sistency. She came repeatedly to the wall of the nest ap- 
parently empty-handed, made actual mud in her jaws 
for short periods and then went away. Working thus, 
she continued to remove the foreign portions of the nest, 
carry the mud to a certain cell and there to fashion her 
own dainty little thimble-shaped cells. Often, as she 
worked, her hind legs extended out to view, and fre- 
quently I could see her curl the abdomen under the body, 
as previously described. Again I tried hard to deter- 
mine the question which had puzzled me on previous 0¢c- 
casions, whether the water oozes out of the tip of the 
abdomen when it is so inflexed or whether the drops come 
from the mouth and are whipped into place by the tip 
of the abdomen as it begins to rub down the mud, but 
again I was unsuccessful in the dim light. 
The speed of her work may be judged from the fol- 
lowing sample of her comings and goings, and the num- 
ber of mouthfuls of mud removed after each trip. She 
went out at 5:40 p. m., returned at 5:42; out two min- 
utes, then removed 8 mouthfuls of mud and worked it 
into her own architecture, consuming 6 minutes at the 
task; out again at 5:48, in at 5:49, absent one minute, 
removed 7 loads of mud in the same fashion in the fol- 
lowing 6 minutes; out for 2 minutes, then transferred 
6 loads of mud to her own structure in three minutes; 
out again for three minutes, and in the following 5 min- 
utes took out 6 loads of dirt. 
