STUDY ON THE DEATH-FEIGNING OF BELOSTOMA a 



feint, the insect often retaining possession of, and keeping the 

 styHform mandibles and maxillae sunk into the prey. 



3. Death-feigning postures: When Belostoma is handled in 

 the manner just described, it usually assumes a definite and 

 constant attitude while in the death feint. When the thumb 

 of the right hand is placed in contact with the abdomen behind 

 the last pair of legs, instantly every femur is projected upward 

 (the insect being held ventral surface uppermost) at almost 

 right angles to the long axis of the body. The claw-like tibia 

 and tarsus of the front pair of raptorial limbs is held tightly 

 within the groove of the femur, while either the tibiae or the 

 tarsi of the middle or the hind pair of legs may be crossed. 

 Figure 2 shows the position of the limbs from a lateral view. Al- 

 though all Belostomas when handled in the manner just des- 

 cribed, can be induced to assume this death-feigning posture 

 under normal conditions, yet they often assume a different atti- 

 tude when taken out of the water. 



If one stops to examine a number of feigning Belostomas 

 which have been raked or scooped out of the water or taken out 

 of an aquarium in the palm of the hand, one usually finds that 

 the legs are folded against the ventral surface of the bDdy as 

 shown in figure i. A femur of the raptorial limbs, with the 

 claw-like tibia and tarsus within the groove, is held close to 

 either side of the head. The tibiae of the posterior pairs of legs 

 are drawn beneath the body and held close to their respective 

 femora so that but little more than the femoro-tibial joints are 

 visible from a dorsal view (fig. 3). 



There is no characteristic position which Nepa assumes while 

 simulating death, the attitude taken depending mainly upon the 

 position of the legs just previous to the death feint. Thus, while 

 in some cases the middle and hind pairs of legs may be extended 

 straight out laterally, in others, again, they may be held backward 

 below the body. All sorts of intermediate positions of the pos- 

 terior pairs of legs may be assumed. The front pair of legs, how- 

 ever, are usually stretched forward or the tibia and tarsus of each 

 leg may be bent back fitting into the groove of the femur. If 

 the insect, either while in the water or out of it, is rolled over 

 and over laterally, the legs are forced to assume a characteristic 

 position; the front pair are stretched forward with the tibia 

 and tarsus either extended or bent back upon the femur, while 



