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162 Trans. Acad. Sci. of St. Louis 
Group 3. Visitors. The insects and animals which 
dropped into the community accidentally, or in quest of 
shelter or food. They very often influenced the inhabi- 
tants, the members of groups 1 and 2, in two ways: by 
eating them or by becoming food for them. 
Group 4. Parasites. This contains the names of 
parasites whose hosts are listed in groups 1 and 2. 
(b) Pioneer life on the clay bank. 
The pioneers, those which blazed the trail, those which 
first came from elsewhere and discovered the clay bank 
and homesteaded it, and made it easy for others follow- 
ing to live near them or in their old abodes, or to para- 
sitize their children—these are first considered, and are 
listed in order of their importance. With this pioneer 
life as a foundation for a community, the other chapters 
that follow will point out their interrelations, sometimes 
simple, sometimes indifferent and sometimes complex. 
The carpenter-bee, Xylocopa virginica. Drury.” 
In the Spring of 1917, the place was visited at in- 
tervals to fix the date of the appearance of the first life. 
The carpenter-bee, Xylocopa virginica, was the first to 
appear. On June 15, perhaps a dozen of the insects 
were at work enlarging the tunnels in the wooden rafters 
of the porch above the clay bank. They were all doing 
precisely the same thing at this time, enlarging the holes 
and kicking out the sawdust. The flickering streams of 
golden grains falling in the sunlight from sources un- 
seen would have attracted the attention even of persons 
unaccustomed to observations of this kind. Judging from 
*All of the material has been identified by expert entomologists, 
ose names appear in brackets along with the specific name of the 
i; 
