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entrance of Spoon River, the conditions are considerably ameliorated 

 and numerous tolerant insects and other forms of life are found. This 

 pollutional or upper mesosaprobic condition obtains to near mid-distance 

 between St. Joseph and Sidney where the water becomes still cleaner, and 

 may be considered mesosaprobic, beta, or contaminate, in the classifica- 

 tions already cited. At or near the village of Sidney, the exact place 

 varying with the season and amount of rains, the condition of the stream 

 has become such that it supports a fauna that may be considered as 

 oligosaprobic, or that normal to clean water, and this continues to the 

 union of the stream with the Vermilion River. 



The conditions by stations may be briefly summarized as follows : 



Station i. — Salt Fork stream above the sewer outlets ; clean-water or 



oligosaprobic fauna. (Check Station) 

 Stations 2, J. — Pollutional or mesosaprobic, alpha. 

 Stations 4-9, Ji. — Septic or polysaprobic. 



Stations 10, 12, /j, 2g, ^o. — Pollutional or mesosaprobic, alpha. 

 Station 11. — Spoon River ; clean-water fauna or oligosaprobic. 



(Check Station.) 

 Stations 14, 15, 26-2S, 32. — Contaminate or mesosoprobic, beta. 

 Stations 16-25, 33- — Clean-water, or oligosaprobic. 



Station i. — Taken on the Salt Fork at the bridge over Market Street, 

 Urbana, in Crystal Lake Park, July 20. Water clear, the fauna strictly 

 a clean-water one. 



Ephemerida. Ephemeridae : Hcptagcnia sp.", naiades. 



Cacuis sp., possibly diminiita Walk, 

 Hemiptera. Veliidae : Rliatjoz'clia obcsa Uhl. 



Gerridae: Trcpobatcs pictus (H. S.) 

 Trichoptera. Hydropsychidae : Hydro psyclic sp. 



Decapoda. Canibants sp., abundant. 



Station 2. — The Boneyard stream, near the Big Four Shops, Urbana, 

 immediately before it unites with the Salt Fork, July 20 The stream 

 here is about eight feet wide, heavily polluted on the south side, the north 

 three feet much clearer. Depth approximately one foot. Bottom gravel, 

 without much sludge. 



Hemiptera. Corixidae. 



Coleoptera. Dytiscidae : Laccophilus proximus Say, adults. 



Diptera. Chironomidae : Tanypiis sp., two larvae. 



Sludge-worms, Tubificidae, abundant. 



Station J.— Salt Fork, 100 feet below the entrance of the Boneyard 

 stream, July 20. Collections made in the riffles where the water was 

 fairly well aerated in spite of the pollution. 



Coleoptera. Haliplidae: Pcltodytcs 12-punrtatus (Say), adults. 



Dytiscidae: Laccophilus proximus Say, aduUs. 

 L maculosus (Germ.), adults. 



