453 



Coleoptera. Gyrinidac : Dliiciitcs aincriranns Say, :xdnh9i. , 



Dryopidae : Hclichus litlwphihis (Germ.), adults. 

 Heliiiidae : Stcnchnis sp., larvae and adults. 



Diptera. Tipulidae : llrioccra sp., possibly gibbosa Doane, 



larva. 



Station 3^. — The bridge at Sidney, re-check on September (equals 

 Station 16). Conditions are about as on the previous examination 

 (August 9) except that the water is hij^jher due to heavy rains. A farmer 

 states that until three years ago the stream was pure and supported many 

 fish. The past two years, however, the stream became polluted, although 

 the water looked clear, and all life died out. In 1921 the .stream was 

 muddy and vertebrate life re-appeared, this including certain fish, frogs, 

 and turtles. It is of interest to note that the following summer (1923) 

 the stream was again badly polluted and vertebrate life, including virtu- 

 ally all of the fish, was destroyed to a distance of two or three miles 

 beyond Sidney. The exact nature of the pollution has not been ascer- 

 tained, although it seems probable that it was a waste product of some 

 one of the factories of Champaign and Urbana. Officers from the State 

 Fish Commission who were sent to examine this condition in 1922 at the 

 instance of the local Fish and Game Clubs, reported that it might be 

 some years before the stream re-established its former condition. 

 Odonata. Coenagrionidae : EiialUKjina sp., naiades. 



Hemiptera. Corixidae : adults and nymijhs. 



Nepidae: Ranatra americana (Mont.), adults. 

 Hydrometridae : liydromctra martini Kirk., adults. 

 Notonectidae : Bucnoa platycnemis Fieb., adults 

 and nymphs. 

 Coleoptera. Dytiscidae: Laccophilus pniximns Say, adults. 



L. uiaculosHS (Germ.), adults. 

 Hydro poms .sp. 



Station j6. — The Shakerack Bridge, re-check on September 9 (equals 

 Station l.")). The second collection revealed some species that were not 

 noted on the former visit. Stream muddy, with no bottom vegetation. 

 Ephemerida. Ephemeridae : CaUibactis sp., pi)ssibly ferruginea 



Walk., naiades abundant. 

 Odonata. Libellulidae : .S" A'/n/ic/rinn sp., naiades. 



Hemiptera. Corixidae : adults and n3-mi)hs abundant. 



Coleoptera. Dytsicidae: Laccophilus proxiums Say, adults 



and larvae abundant. 

 Di])tera. Chironnmidac : Froc/od/iu sp., larvae. 



Chironomus sp., larvae abundant. 

 Station 3/. — Benchmark 66, re-check on September 9 (ecjuals Sta- 

 tion 14). A very abundant fauna at this time. 



Ephemerida. I'.iihcmcridae : CaUibactis sp., jiossibly ferruginea 



Walk., naiades. 



