310 Journal of Comparative Neurology and Psychology. 



grab for it, and, if successful in seizing it, proceeds to suck out 

 its blood in the manner described by de la Torro Bueno. 



In locomotion, either by swimming or walking, the anter- 

 ior limbs do not usually play a part ; they are held straight in 

 front of the body and are employed only occasionally to aid in 

 changing the direction of locomotion or to clamber over some 

 obstruction. Out of the water Ranatra walks rather awkward- 

 ly. Its long slender second and third pairs of legs are articu- 

 lated close together near the center of the body and the insect 

 is frequently tilted over so that one extremity or the other 

 strikes against the surface over which it walks. While Rana- 

 tra is capable of flight, it rarely if ever flies to lights at night as 

 many other aquatic hemiptera do ; I have never seen any 

 specimen around electric lights where other insects are found 

 in abundance. 



Ranatras pass the winter in the adult state. I have col- 

 lected numerous specimens in a small stream north of Ann 

 Arbor late in November, but on visiting the same locality dur- 

 ing a thaw in January following, although a diligent search was 

 made in their favorite habitat among aquatic plants and by dig- 

 ging in the mud in the sides and bottom of the stream, I did 

 not obtain a single specimen, although Zaithas and water boat- 

 men were found to be quite common. Possibly the Ranatras 

 burrowed more deeply than I could dig with the apparatus 

 employed, although the general form of the animal renders this 

 supposition improbable. Egg laying occurs in the spring. The 

 eggs are long and narrow and furnished at one end with a pair 

 of filamentous processes which, according to Korschelt, have 

 a respiratory function. In ovoposition the female inserts the 

 eggs into the stems of aquatic plants, or even into wood, the 

 filaments projecting from the exposed ends. 



Ranatras make a feeble sound by rubbing the bases of the 

 anterior legs against the lateral processes of the prothorax. 

 When a Ranatra is picked up in the fingers one can feel a slight 

 tremor when the animal stridulates, although the sound is so 

 faint that it cannot be heard farther than a few inches from the 

 ear. What use, if any, is made of this sound is uncertain. 



