PLATE X. 



PIG. 1. Variety of nest of Pelopaeus coeruleus, showing lumps of mud 

 plastered on outside. 



FIG. 2. Vertical cell of nest of Pelopaeus coeruleus. 



FIG. 3. Horizontal cells of nest of Pelopaeus coeruleus. 



FJG. 4. Nervous system of Halyctus. (After Marchal.) 



FIG. 5. Nest of Diodontus americanus, natural size. 



FIG. 6. Nest of Pompilus quinquenotatus, nearly natural size. 



FIGS. 7-8. Examples of Epeira strix that have been paralyzed and 

 hung up on bean and sorrel plants by Pompilus quinque- 

 notatus, that they may be out of the way of ants while 

 she digs her nest. 



