Table 6. — Number of insects and other organisms per square foot (0.092 m.^) collected in the 

 Sturgeon River before chemical treatment and 1 week, 6 weeks, and 1 year after treatment. Lake 

 Michigan, 1963 -6-; 



Organism 



Insects: 

 Plecoptera 



Nemouridae 



Perlidae 



Chloroperlidae . 



Other 



Ephemeroptera 



Ephemeridae. . . . 



Caenidae 



Heptageniidae. . 



Leptophlebiidae 



Baetidae 



Other 



Odonata 



Gomphldae 



Other 



Megaloptera 



Corydalidae 



Hemiptera 



Hebridae 



Triohoptera 



Rhyacophilidae. 



Psychomylidae. . 



Hydropsychidae. 



Hydroptilidae. . 



Phryganeidae. . . 



Leptoceridae. . . 



Other 



Lepidoptera 



Pyralididae. . . . 

 Coleoptera 



Elmidae 



Other 



Diptera 



Tipulidae 



Simuliidae 



Chlronomidae . . . 



Heleidae 



Tabanidae 



Rhagionidae. . . . 



Empididae 



Other 



Other invertebrates 



Bryozoa 



Annelida 



Crustacea 



Hydracarina , 



Mbllusca , 



Total 



Riffle areas 



Pre- 

 treatment 



1 year 



Sand and detritus areas 



Pre- 

 treatment 



4 

 1 

 5 

 











17 



23 



15 







9 

 



1 

 2 

 9 

 4 

 10 



155 

 



3 

 3 



45 



7 

 

 13 

 

 6 



4 

 4 

 9 



1 











10 



31 



14 



1 



6 



1 







1 



12 



1 



10 







1 



Number per square foot 



2 





 

 



1 

 

 6 

 5 

 97 

 1 



10 



1 





 2 

 3 







4 

 

 9 

 17 

 35 

 



5 

 





 

 

 



14 

 59 

 

 

 3 

 1 



1 

 



7 

 





 1 

 248 

 15 

 2 

 

 

 1 





 

 2 

 10 

 



1 year 





 

 2 

 



25 

 62 

 27 

 28 

 18 

 





 









 3 

 

 

 14 

 1 



11 

 4 



3 



24 



137 



11 











2 











9 



1 



10 



12 



348 



353 



340 



205 



405 



Percentage of 

 pretreatment number. 



100 



98 



100 



56 



110 



