HUNGERFORD: AQUATIC HEMIPTERA. 247 



Culture 16168. (Oscillatoria.) 



History and Diagnosis. Pure culture of Oscillatoria obtained from 

 water analysis laboratory. No animals in this culture. 



Corixids Added. Placed A. alternata here July 28, On August 1 

 they were observed to work at food gathering. August 8 dissected the 

 Corixids : 



One male. Digestive tract nearly empty. A brown mass of indeter- 

 minate material in bend of mid-gut. 



Three females. Tracts nearly full of reddish brown material, indeter- 

 minable. 



One male. As above, plus considerable number of Oscillatoria fila- 

 ments, some of them still well preserved. 



Culture A, August 19. (Green pond ooze.) 

 Histo7-y and Diagnosis. Gathered some shiny, greenish ooze from the 

 bottom of a mud puddle. This contains various species of Algae, especially 

 the blue greens, and among the free moving Englenae and diatoms. 



Corixids Added. Several specimens of a small species of Corixid added. 

 In twenty-four hours examined them. Their stomachs were packed with 

 green matter. This consisted of much disorganized unicellular plant cells, 

 Oscillatoria filaments so abundant that they bound the masses together, 

 Englenae and diatoms. This one study would satisfy one beyond any 

 question of a doubt as to the plant origin of their food. 



Culture B, August 19. (Water Bloom muddy.) 

 History and Diagnosis Gathered some of the green scum from a stag- 

 nant, muddy pool and placed it in a Petrie dish. 



It was teeming with life. Plants: Chlamydomonas, small species of 

 Englena, large species Englena, diatoms, some Oscillatoria, and a few 

 filaments of an alga. Englena dominant. Animals: Arcella abundant 

 for this genus. Amoeba stuffed green with ingested unicellular plants. A 

 few Paramecium and Heterotrichs. 



Corixids Added. A. alternata and R. acuminata placed upon this cul- 

 ture. Examined following day. 3 j i? aciiininata nearly empty. An- 

 other contained a small ball of yellowish green material in the bend of 

 the mid intestine. This was dissected out entire and resisted separation 

 as if held together by fibrous material. Most of this mass was dis- 

 organized unicellular plant particles, such as noted in the Amoeba. Two 

 clear shafts of some filamentous algae and a membrane of some Crustacea 

 and A. alternata mid-intestine packed full of green material, which re- 

 sisted separation like the above. Mostly bits of greenish material, parts of 

 unicellular plants, many encysted, plenty of bright green cells nearly cir- 

 cular in outline. Red spots of material from disorganizing Englena. 

 Two filaments of Oscillatoria, a couple of diatoms. Most material is of 

 Englena origin, as shown by the fact that fresh Englenae still green are 

 abundant, and all stages of disorganized material are to be found. Thus 

 the yellowish granular material can be traced to its unicellular plant 

 origin. 



