Food of Corixids. 
INTRODUCTION. 
In a paper which appeared in the Journal of the New York 
Entomological Society, 1917, the writer called attention to the 
fact that the water boatmen gather their food supply from 
the ooze at the bottom of the pool. This flocculent material 
they sweep into their mouths by means of the flat rakes of 
their fore legs. In view of the discrepancy that exists between 
textbooks and the writer’s notes on the subject, he deems it 
worth while to present under this chapter heading some of 
his data relating to the question, even at the expense of the 
general balance of the work. Therefore, material that would 
otherwise be presented in a single paragraph is given a larger 
treatment under the following outline: 
OUTLINE OF STUDY ON FOOD OF CORIXIDS. 
Historical sketch. 
General habits of Corixids. 
Structural adaptations. 
External. 
Internal. 
Studies relating to the food of Corixids. 
Object. 
General plan of experiments. 
Pure cultures and surveyed cultures to determine essential 
forage and selected forage. 
History of cultures. 
Survey of culture. 
Analysis of stomach contents. 
Technique. 
Special studies. (Selected as typical.) 
HISTORICAL SKETCH. 
De Geer, 1778, says that Corixids are carnivorous, and 
Latreille, 1802, says, also, ‘““Leurs habitudes sont carnassieres.”’ 
Since that time all textbooks and treatises relating to the 
general habits of water bugs either state that they are preda- 
tory or are silent regarding their feeding habits. In a care- 
ful review of the literature the writer has been unable to find 
a suggestion on the part of any one to the effect that the 
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