March, I9I7-] HUNGERFORD : FoOD HaBITS OF CuRIXIDS. 5 



[In all the aquatic forms, both gymnoceratous and cryptoceratous (with 

 the possible exception of the Corixidas) the anterior legs are raptorial. In all 

 the femora are dilated — in some moderately, in others enormously.] 



5. KiRKALDY, G. W. Guide to the Study of British Waterbugs. Entomologist, 



1899, p. III. 

 (Corrects above statement by excepting Hydrometra.) 



6. KuHLGATZ, Theodore. Rhynchota in Brauer's Die Siisswasserfauna 



Deutschlands, 1909, heft 7. 

 (See page 87, " Nahren sich vom Aussaugen anderer kleiner Wassertiere, 

 besonders Insecten. . . .") 



7. OsBORN, Herbert. Phylogeny of Hemiptera. Proc. Ent. Soc. Washing- 



ton, III, pp. 185-190. 

 (Considers Cryptocerata as highly specialized.) 



8. Patton, W. H. Notes on Phylogeny of Hemiptera. Ent. News, VH, 202. 



(States that he believes the waterbugs are of high rank.) 



Plate I. 



Fig. I. Cephalic view of head and forelegs of a female Corixid. The 

 left leg has been turned in a position to show the nature of the paler surface, 

 which in the right leg is appressed to the face. 



Fig. 2. The extremity of the beak of a Corixid from a specimen cleared 

 in caustic potash. It shows two of the stylets and the nature of their tips. 

 It also reveals the fact that they are strongly chitinized only for a short dis- 

 tance. They afford a remarkable contrast to the stylets of Hydrometra, which 

 are exceedingly long and capable of being exserted beyond the tip of the beak 

 a distance nearly as great as the length of the beak itslf. 



Fig. 3. The tip of a stylet of Hydrometra to show its equipment for re- 

 taining prey. These stylets when not exserted extend well back into the 

 peculiarly long head of the bug. Hydrometra spears its prey and depends 

 upon the effectiveness of its barbed stylets to hold and its poisonous salivary 

 injections to subdue the victim. 



Fig. 4. A view of the pala of the right foreleg of a female boatman. An 

 efficient device for scooping up and bringing to the mouth the sedimentary 

 material in the deposits on the bottom of the pool. 



Fig. 5. Lateral view of the head and forelegs of a male Corixid, to 

 illustrate the process of food gathering. The arrows indicate the direction 

 of the food material. The stylets are shown exserted, one foreleg passing 

 food material across the face and over the buccal opening, the other in the 

 act of gathering material. 



Fig. 6. The right foreleg of a Naucorid seen in ventral view. This 

 presents the usual modification of the foreleg for grasping and is shown in 

 contrast to the type of the foreleg of the boatmen, so long believed to be 

 predaceous. 



Note. — I am glad to acknowledge my indebtedness to Miss Ellen Edmon- 

 son, a student in the department, for figs, i and 4 ; the remaining figures are 

 my own. 



