DeRyke and Scott 19 



112 mm. About 8 cmm. of Potamogeton plant tissue. 



114 mm. Head of Chironomus larva; stomach well filled with plant tissue 



and 2 round worms. 

 112 mm. Small portion of Myriophyllum plant tissue; the wings of an 

 adult damsel-fly; 1 odonatid nymph; 1 Chironomus larva; 1 tricop- 

 teron; 3 tenthredinidae. 



115 mm. Stomach well filled with portions of Potamogeton plant tissue 



and fragments of damsel-flies; Chironomus larvae and water mites. 

 94 mm. 8 fish eggs; 1 water mite; about 4 cmm. of animal tissue, un- 

 able to identify. 



112 mm. Badly macerated, half-digested mass of animal tissue. 



125 mm. 1 adult odonatid; 7 fish eggs. 



Collection 2U 



July 27, 1920. Potamogeton, Elodea, algae, Vallisneria spiralis, Chara, 

 duckweed, Myriophyllum, Ceratophyllum; marl, peat and vegetable debris; 

 four feet; clear; clear and cool; 11:00 a. m. ; seine. 



Fishes examined in this collection 



Lepomis pallidus (bluegill) Mitchill. 



128 mm. Stomach well filled with Spirogyra and aquatic annelida aver- 

 aging 3 mm. in length; about 300 aquatic annelida and 5 Chironomus 

 larvae. 



Ill mm. 3 dragon-fly larvae and 10 large fragments; Spirogyra filaments; 

 small piece of Nais 3 mm. long; 1 tricopteron larva and 5 aquatic 

 annelida. 



Collection 25 



July 27, 1920. Potamogeton, dense growth of algae, Elodea, Vallisneria 

 spiralis; sand and mail; two feet; clear; clear; 11:30 a. m.; seine. 



Fishes examined in tliis collection 



Perca flavescens Mitchill (yellow perch). 



36 mm. 2 Chironomus larvae; 1 pupa; 193 cladocera; 24 Cyclops. 

 39 mm. 464 cladocera. 

 Lepomis pallidus Mitchill (bluegill). 



16 mm. 21 Cyclops; diatoms and desmids. 

 13 mm. 6 cladocera; a few algae filaments. 

 11 mm. 3 cladocera; 12 Cyclops. 

 142 mm. Partially-digested animal tissue; grains of sand and debris; 1 

 aquatic annelida; 1 dipteron larva; 1 dipteron pupa; 3 mutilated 

 flies and many small portions of flies. 

 21 mm. 115 cladocera; 1 Cyclops. 

 140 mm. 2 nematoda; about 6 cmm. of algae and Potamogeton plant 

 tissue; 23 aquatic oligochaeta, sand and debris; 1 fly; 1 hymenopterus 

 insect 5 mm. long. 

 68 mm. 3 mutilated flies; many small portions of flies. 

 82 mm. 3 nematoda; 1 midge pupa; 1 Planorbis; 1 stone-fly nymph; a 

 few Spirogyra filaments; 316 cladocera; 91 Cyclops; 4 Chironomus 

 larvae; 3 ostracods; 7 water mites. 



