1899] RE GENERA TION 3 t 5 



investigate the process of regeneration in the Phasmidae more fully, 

 and he found that artificially-caused defects were made good only from 

 particular regions. Eegeneration from the cut end takes place only if 

 the tarsus or the lower third of the tibia be cut off. If the limb be cut 

 through higher up, the remaining portion of the leg is thrown off, and 

 regeneration starts from the point of fusion of the trochanter with 

 the femur, these parts not being connected by a joint as in other 

 insects, but forming a thin suture at their union, and it is there that 

 the breaking off of the limb takes place. The same state of things 

 prevails among crabs and shrimps, in which M'Culloch has described 

 the mechanism which brings about self-amputation of a limb when 

 certain stimuli, such as compression or amputation, are brought to bear 

 011 it. At this point regeneration takes place, and here, therefore, the 

 power of regeneration is localised. Both the capacity for autotomy and 

 the power of regeneration limited to certain definite regions obviously 

 imply not " primary adaptiveness " (ZiccckmiissigJceiten), but secondary 

 arrangements, adaptations to perfectly definite and special conditions. 



In order to learn something of these conditions in the case of the 

 Phasmidae, Bordage instituted various experiments. He placed the 

 insects with some birds, and observed that the latter — as indeed was 

 to be expected — never merely injure the insects but invariably kill 

 them outright by pecking at them with their bills. This is particularly 

 true of the king-fisher of that region, Acridothercs tristis, which is a 

 great destroyer of the grasshoppers and Phasmidae. 



Birds, therefore, are never the cause of autotomy and regeneration 

 of a limb ; they are simply among the eliminators of these insects, not 

 among the moulders of their regeneration-arrangements. But it is 

 otherwise with small lizards. These {e.g., Calotcs versicolor) often 

 seize the Phasmid by the body and swallow it at once, and this 

 happens particularly often to the larva. But when an insect is full 

 grown and its assailant is relatively small, the latter usually only 

 succeeds in seizing its victim by one of the long legs, and then it 

 tries to work its way gradually upwards with its mouth so as to get 

 hold of the body itself. ^It does not bite very deeply, but presses 

 the legs with just sufficient force to prevent the prey escaping, the 

 insect meanwhile resisting by clinging convulsively to the nearest 

 object. The stimulus supplied by the compressing teeth and the 

 forcible pulling at the leg may cause the breaking off of the latter at the 

 suture, and if the insect then lets itself fall from the twig on which 

 it is sitting, it is saved. But, according to Bordage, in most cases it 

 does not do this, but tries to run away, and is then easily recaptured 

 and overpowered by the Calotes. 



It happens sometimes, though not often, that the lizard catches 

 hold of the leg by the tip only, and breaks it off, and thereupon 

 regeneration ensues as already described, without the preliminary 

 throwing off of the whole leg, which occurs only in response to 



