160 Journal of Entomology and Zoology 
her task, but she had ad\ anced less than one inch. Fig. 1 shows this 
tunnel and the rate of progress. It seemed to he a typical case. 
I have known one tunnel to he several weeks under construction. 
Their average length is from four to six inches. Those of greater 
distance, I think, are the result of more than one season's work, 
having been lengthened from year to year. 
While digging, the bee slowK- tui'iis in the burrow, requiring from 
thirty minutes to an hour to complete the cycle. Observation 
showed no regularity or uniformity either in rate or tiirection of 
turning. 
I ha\'e ne\er found orpifex except in reasonablv large aggrega- 
tions. If some ad\'enturous female begins work in a new locality, 
that locality is sought out by others until almost e\"ery a\ailable 
timber is honey-combed with tunnels*. From one surface entrance 
there are usually several tunnels leading away. Figs. 8 and 9 are 
typical in this respect. This habit doubtless ser\-es well in the reduc- 
tion of labor and also rctluces the danger from enemies. A third 
advantage gained is the mutual protection against changes of tem- 
perature during the winter, for T found these tunnels, on cold days, 
literally packed full; in manv cases two rows of bees lying side 
by side in the same tunnel. 
Other than the points mentioned I find no hint of true community 
life. Males and females are about equal in number, and in the 
rearing of young they beha\e as other solitary bees so far as I am 
able to learn. \o food is stored for winter but on warm days 
thev come forth in search of food, a temperature of about 20 deg. 
to 21 deg. C. being sufficient to inx'ite them out. 
Life History: Having finished her tunnel the female begins to 
pro\ision it with bee-bread which she makes from pollen and regur- 
gitated nectar. After accumulating a mass about as large as her 
own bodv she lays an egg upon it and walls up that part of the bur- 
row with a partition of chijis of wood cemented together in the 
form of a spiral (Fig. 2), as Comstock has described in the case 
of Xxlocopti zirg'niica. Examination showed no uniformity in the 
direction of this spiral. I found among the partitions built by the 
•This mav be due to the scarritv of reHv 
