432 Trans. Acad. Sci. of St. Louis 
female returns with load of mud, takes just one-half min- 
ute to apply it in half ring on right side, and departs; 
3:08, male takes his stand an inch below the nest; 3:12, 
female returns with load and applies it to left side; male 
waits at her ‘elbow’ and as she departs he again tries 
the nest, but poor fellow, he finds it still too small; 3:14, 
female leaves; 3:15, returns and applies mud; 3:15%, 
out; 3:16%4, in; 3:17, out; 31814, in; 3:19, out; the male 
meanwhile fussing about.’’ I was then obliged to leave 
for a time, but this gives an idea of the intense industry 
of the little female. When I returned at 4 o’clock the 
nest was an inch long. Soon the male came back from a 
journey somewhere and went directly into the nest. It 
was large enough now to completely cover him! Once 
securely inside, he hummed almost incessantly. He sang 
while she worked, and she sang at her task, but the 
sounds were two distinct tones; his note was one continu- 
ous, low trill, while hers was intermittent and more loud 
and shrill. Once inside, he did not again venture out., 
He eventually ceased buzzing in there, but if one poked 
him with a straw, he would promptly resume it; he made 
no sign of fiying out or attempting in any way to protect 
the nest. 
The nest, now one inch long, had 24 rings; each ring 
represented two balls of mud; the little worker had 
brought and applied 48 loads of mud between 2:30 and 
4:30! The male was now happy. She had provided him 
with a roof; I suppose she will next bring him food and 
clothes. Homo sapiens might question her claim to 
credit for intelligence in her action, but could his be in 
closer imitation of the conduct of day-before-yesterday 
in our race? 
A nest of T. politum consisting of four tiers or ‘‘pipes”’ 
showed by the condition and size of the larvae within 
