ANIMAL AND ITS ENVIRONMENT 467 



elms. The table below indicates some of the insects to be found in 

 each stage of this developmental series. After the name of each 

 insect is given, in parentheses, its principal food. 



Succession on tpie Canadian Eiver Flood Plain. (Data From Hefley.) 



STAGE in development 12 3 4 5 6 



Paralimma appendiculatum x* 



Fly 



Heterocerus pallidus x 



Beetle (Algae and detritus) 



Bendidion laevigatum x x 



Beetle (Algae and detritus) 



Cincindela hirticollis x x x 



Tiger Beetle (small insects) 



Cinindela cuprascens x x x 



Tiger Beetle (small insects) 



Cinindela punctulata x 



Tiger Beetle (small insects) 



Mutillidae x 



Velvet ants (insects and spiders) ' 



Apion pennsylvanicum x 



Weevil (cocklebur) 



Haltica bimarginata x x x 



Beetle (willow) 



Phalacrus politus x 



Beetle (willow) 



Stictocephala lutea x 



Tree hopper (willow, cottonwood) 



Cicadella gothica x 



Leafhopper (willow) 



Dorytomus squamosus x 



Weevil (willow) 



Strongylocornis stygicus x 



Bug (coral berry) 



Epitrix brevis x 



Flea Beetle (Miscellaneous plants) 



Brief descriptions of stages: 



1. Mud flat with blue-green algae, later liverworts. 



2. Sedges, willow and cottonwood seedlings in addition to 1. 



3. Second level. Sand, sedges, willows, cottonwoods, cockleburs. 



4. Third level. Grasses, willows, cottonwoods. 



5. Third level. Cottonwoods, fewer willows. 



6. Fourth level. Elm-oak forest with shrub undergrowth. 



•x indicates the presence of the species as an important member of the com- 

 munity. 



