PLATE XXIX. 
Fic. 1. 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 sur- 
face, which in the right leg is appressed to the face. 
Fic. 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 distance. They afford a remarkable contrast to the stylets of 
Hydrometra, which are exceedingly long and capable of being exserted be- 
yond the tip of the beak a distance nearly as great as the length of the 
beak itself. 
Fic. 3. The tip of a stylet of Hydrometra to show its equipment for 
retaining prey. These stylets when not exserted extend well back into 
the peculiarly long head of the bug. Hydrometra spears its prey, and de-— 
pends upon the effectiveness of its barbed stylets to hold, and its poison-— 
ous 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 sedi- 
mentary material in the deposits on the bottom of the pool. 
Fic. 5. Lateral view of the head and forelegs of a male Corixid, to 
illustrate the process of food gathering. The arrows indicate the direc- 
tion 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. 
Fic. 6. The right foreleg of a Naucorid seen in ventral view. This i 
presents the usual modification of the foreleg for grasping, and is shown | 4 
in contrast to the type of the foreleg of the boatmen, so long believed to 
be predaceous. Plate used in Jr. N. Y. Ento. Soc. XXV. 4 
(324) 
