164 Psyche [Sept.-Dee. 
ture being built, so long as this is possible, that the abdomen at 
times also functions in the building, as seen by Fabre in the 
case of O. tridentata , a species which, however, uses mud as its 
building material. 
After the partition is completed, the next step is not im- 
mediate resumption of foraging among the flower blossoms, but 
instead laying off a “building line” for the next partition. This 
preliminary structure, made of mud by O. tridentata , of leaf 
pulp by our Osmia, is a ring of the material applied to the glass 
tube at the appropriate place, to “mark off,” so it looks to the 
observer, the limits of the next cell. 
When first seen at this work the bee was working with her 
head outward, tail inward. She had gathered new leaf pulp for 
the purpose and backed into the cell. With her tail touching 
the last partition she was laying off the site of the next one, not 
yet needed; and the whole process looked as though she were 
measuring with her body, thigmotactically, as it were. Indeed, 
our notes contain the words “Is she measuring?”, an expression 
Fabre had used fifty years before in connection with triden- 
tata. 
Parenthetically be it remarked that nowhere in the field of 
animal behavior is more anthropomorphism exhibited than 
among students of the solitary hymenoptera. Fabre himself 
has a unique way of setting up straw effigies of teleology and 
anthropomorphism, only to knock them down. With the latter 
he is quite successful but, being an advocate of the notion of 
perfection and invariability of instinct, his preconceived teleo- 
logical explanations sometimes find justification in “appropri- 
ate” experiments. 
All would be well with the idea of Osmia’s “measuring” were 
it not for the fact that she seldom works with the body oriented 
as indicated! More usually she works with tail outward, not 
inward; nor does she leave the next to secure the few loads of 
material needed for the ring. Instead, she filches the “mortar” 
from the finished partition, backing up with each mandible-ful 
to apply it to the circular line in question. Under such circum- 
stances there is no suggestion of “measuring” even to anthro- 
pomorphic eyes. 
The last cell is usually empty; that is, there are usually two 
closing partitions, the outside one, which is flush with the end 
of the tube, being generally the thickest of all. 
