448 



Mesoveliidae : McsovcUa mulsanti White, adults 



and nymphs. 

 Hydrometridae : Hydromctra martini Kirk, adults. 

 Belostomatidae : Belostoma flu mi lie it in Say, com- 

 mon, the males with egg-masses. 

 Neuroptera. Sialidae: Sialis infumata Newm., larvae. 



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



Hydrophilidae : Tropistcrmis glabcr (Hbst.), lar- 

 vae and adults. 

 Berosus striatus (Say), larvae and adults. 

 Diptera. Chironomidae : Chironomus sp., a few larvae. 



No sludge-worms are present. Cambarus sp. and HyalcUa knickcr- 

 bockeri are common. The occurrence especially of Hcxagcnia and Siaiis 

 point to clean-water conditions. These genera were last taken at Station 

 11, the Spoon River. Tadpoles, and young catfish and sunfish are com- 

 mon. 



Station ly. — Five miles east of Sidney, about three miles west of 

 Homer Park, August 17. At the place where collections were made the 

 stream has a bottom that is almost pure clay. Small fish of fihgerling 

 length are abundant and many set-lines of the natives indicate good fish- 

 ing. Insect life in this clay bottom is not large or varied. 



Odonata. Aeschnidae : Coof/'/nfjr sp., a few naiades. 



Hemiptera. Corixidae : common. 



Gerridae: Mctrobatcs hcspcrius Uhl., nymphs of 

 the second and third inslars common. 



Neuroptera. Sialidae : Sialis infumata Newm., lan-a. 



Coleoptera. Gyrinidae: Dincutcs amcricaitus Say, adults. 



Station 18. — Below the dam at Homer Park, August 17. Riffles over 

 the broken stone and small pebbles. An entirely clean-water fauna pres- 

 ent. 



Plecoptera. Perlidae : PcrJa sp., naiades. 



Ephemerida. Ephemeridae : Polymitarcys albus (Say), naiades. 

 Ephcmerella sp. 



Caenis sp., possibly diininuta \Vk. 

 Hcptagcnia sp. 

 Bactis sp. 



Chirotenctcs alboinanicafus Ndm. 

 Odonata. Aeschnidae: Ophiogomphus sp., naiades. 



Agrionidae: Hctacrina aincricaiia (Fabr.), adults 



were common, ovipositing in the clean water. 

 Coenagrionidae : Argia mocsta putrida Hag., 

 adults were common, ovipositing in the clean 

 water. 

 Hemiptera. Corixidae: common. 



Hydrometridae: Hydromftra martini Kirk., few 

 adults. 



