Plate IIIA 



Fier. 1. Flowers of the swamp milkweed (Asclepias incarnata) at Station I, d. These were the 

 favoiite haunts of manv flower-visiting insects. (Photograph, T. L. Hankinson.) 



Fig. 2. Crawfish chimney at Station I, </, Charleston, 111. Probably formed by Cambarus gracilis 

 or aiogenes. (Photograph by T. L. Hankinson.) 



