474 M. Edmond Bordage o?i Avtotomy in 



frequent occurrence and may be expressed by a certain 

 number of minutes. 



It has happened that I have pinched, till I crushed them 

 between the finger-nails, several limbs of a nymph, without 

 succeeding in producing autotomy. 



Quite tired out, I placed the insect upon a table : it moved 

 along with difficulty, dragging its legs, which had been 

 rendered useless ; then, after four or five minutes (a quarter 

 of an hour sometimes), the injured api^endages broke off 

 cleanly, not at the points where they were crushed, but always 

 at the spot at which rupture by autotomy normally takes 

 place. Only in a few cases have I seen the crushed limb not 

 separate itself from the thorax. Judging by their lack of 

 vigour and by a certain flaccidity of body, I am led to believe 

 that I was then dealing with nymphs on the point of per- 

 forming an ecdysis. Moreover, the experiments attempted 

 upon them were followed shortly by the death of these insects. 

 The influence of thermic agents seldom gave me good 

 results. A limb which I placed in contact with a lighted 

 match sometimes detached itself after a few seconds ; in other 

 cases it allowed itself to be charred until reduced to a mere 

 stump without becoming detached from the thorax. 



The rapid section of the femur, at whatever point it be 

 performed, does not always produce autotomy (nevertheless 

 this process infallibly occasions the rupture of the great limbs 

 of the grasshopper). Sometimes, after having thus ampu- 

 tated part of the limb in vain, 1 placed a lighted match in 

 contact with the wound, and it was only in certain cases that 

 this produced the spontaneous severance of the stump. 



Since the effect of the bites of ants is identical with what 

 \\ e observed in the case of the adult insects, we will not 

 revert to this point. We may mention, however, that we 

 have never seen the ants succeed in producing the autotomy 

 of all six limbs. 



As we have already stated, the ]jhenomena of autotomy 

 are not exhibited in a regular manner in the Phasmidaj, at 

 least in the species that we have studied. In spite of this 

 our experiments, performed upon a large number of specimens 

 of Monandroptera and UJiajjliiderus ^ have enabled us to 

 establish the fact that in the nymphs autotomy becomes in- 

 creasingly difficult in proportion as these nymphs draw nearer 

 to the ^nal metamorphosis. 



Since the month of September 1896 I have kept in cap- 

 tivity nymphs of Rhaphiderus and Monandroptera, a thing 

 somewhat difficult to do, since these insects normally live at 

 an altitude of upwards of 700 or 800 metres. They browse 



