Holmes, The Reactions of Ranatra to Light. 309 



The general form and dull coloration of Ranatra tend to 

 make it inconspicuous in its natural habitat, especially as it does 

 not reveal its presence by its movements. When lying in the 

 water the long breathing tube through which air is admitted to 

 the body rests at the surface. The two parts of which it is 

 composed occasionally approach and recede from each other, 

 moving the air between them to and fro, an operation which 

 doubtless assists in respiration. Air is prevented from escaping 

 when the valves are separated, by the rows of hairs which line 

 the margins of the concave inner faces of these structures. 



Ranatra is carnivorous in habit, seizing its prey with its 

 anterior raptorial limbs and holding it until it has sucked out 

 its juices. It is quite destructive of fish eggs and frequently 

 attacks and sucks the blood from young fishes. It is also 

 reported to prey upon young tadpoles. De la Torre Bueno^ 

 describes the method Ranatra employs in capturing prey as 

 follows: "When a fly attracts its attention Ranatra very slow- 

 ly, almost imperceptibly, moves its fore legs, with the knife-like 

 tarsus away from the tibia, towards its prey. When the tibiae 

 are almost, or quite, touching the victim the movement is so 

 sudden and quick that one is aware of it only by seeing the 

 prey seized. Sometimes its hold is not satisfactory, and then 

 it will let go with one tarsus, get a firmer grip with that, and 

 then do the same with the other. Once it has the fly securely 

 held, Ranatra slowly approaches it to its extended beak, with 

 which it seems to touch and feel until it finds a suitable spot, 

 and proceeds to a leisurely meal." I have usually fed Rana- 

 tras during the winter on Notonectas, or back-swimmers, as 

 these insects were easily obtained during this time of year. 

 The Ranatras did not pursue the back-swimmers, but as soon 

 as their attention was attracted to the prey they lay quietly in 

 readiness for them with their anterior limbs prepared to quickly 

 seize the small insects should they swim sufficiently near. If a 

 Notonecta strikes against a Ranatra the latter makes a quick 



'Notes on the Stridulation and Habits of Ranatra fiisca Pal. B., Canadian 

 Entomologist, Vol. 35, p. 235, 1903. 



