hungerford: aquatic hemiptera. 243 



for they continued to sweep in dead rotifers and protozoa along 

 with green plant cells. 



Spirogyra Culture. 



It has been stated elsewhere in this paper that Corixids are 

 very largely herbivorous ; that the digestive tracts have been 

 found to contain much chlorophyll. But the finding of pebbles 

 in the stomachs of fishes is not taken as conclusive evidence 

 that pebbles form their food supply. So with the boatmen. 

 The writer felt that chlorophyll might be eaten by herbivores 

 and these herbivores by Corixids, and the digestive tracts of 

 the boatmen would be green. Moreover, even the carmine 

 experiment cited above might be subject to criticism by those 

 who had not made direct observations. Such skeptics might 

 say that the carmine could be ingested by worms, amoebae, 

 etc., and thus, through the eating of these organisms by 

 Corixids, get into the stomachs. The contention that Corixids 

 are largely herbivorous, is obvious to any who repeat these ex- 

 periments for themselves, but to the writer's mind, nothing 

 seals the incontestibility of the facts like the following dem- 

 onstration. This demonstration has been repeated a number 

 of times with three or four species of Corixids. Here are the 

 notes on the first experiment : 



Washed a species of Spirogyra repeatedly in tap water until 

 every organism perceptible under the low-power compound 

 was removed, then placed a few filaments of this in a small 

 Petiie dish and added an adult Palmacorixa bueiioi. It began 

 feeding at once and worked contentedly. It gathered up the 

 green filaments, singly or by the half dozen, and slowly worked 

 them backwards, using its palse like hands, to manipulate the 

 algal threads which it pressed to its mouth. So intent was 

 this bug upon the business in hand, that it was content to lie 

 upon its back and eat, so every detail visible with a high-power 

 binocular was seen. For thirty minutes this bug fed most in- 

 dustriously. The spiral filament, moved from front to rear by 

 the hand-over-hand movement of the fore I'mbs, was pressed 

 to the face, the cell punctured and the green matter with- 

 drawn. See plate XXX. Thus the threads of Spirogyra that 

 were passed between the mouth and the palae of the bug were 

 transformed from threads bright with green spirals to empty 

 and transparent filaments. After a half hour's feeding, the bug 



