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, arid 

 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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