508 M. Edraond Bordage on the Tetrameric 



tated limbs in the larvae and nymphs, and I stated that very 

 frequently the regenerated limbs exhibited only four joints in 

 their tarsi. 



I should say that at that time I had been able to make 

 but a limited number of experiments, and that I did not 

 imagine that I had to deal with a general rule. Since then 

 I have multiplied my observations, and I have clearly proved 

 that the expression " very frequently '''' ought to be replaced 

 by always. I must also make mention of the curious circum- 

 stance that, in the first place, was especially instrumental in 

 causing me to doubt the generality of this rule. 



In the collections of the Natural History Museum of the 

 Island of Reunion (an establishment of which I am director) 

 I had noticed a female Monandroptera of which the second 

 pair of legs appeared themselves to be of equal length, 

 although relatively shorter than the others. Moreover, the 

 tarsus of one of them possessed five joints, while that of the 

 other exhibited only four. My first idea was that in the 

 case of these two limbs regeneration had taken place after 

 autotomy. This seemed then to imply that this regeneration 

 produced sometimes five tarsal joints and sometimes four. 



But measurements taken with the greatest care enabled me 

 to ascertain that the limb with the pentamerous tarsus was of 

 perfectly normal length, though it was owing to the length 

 that, at the outset, I had been led to doubt tlie position given 

 to the second pair of legs by the person by whom the insect 

 had been set. While the anterior legs were stretched straight 

 out in the direction of the axis of the body and the posterior 

 ones were extended at right angles thereto, those of the 

 second pair, quite doubled up, took the form of a V reversed ; 

 and it was just this shortening that had made me believe that 

 the dimensions were smaller. If the limb with the penta- 

 merous tarsus was of normal length, that with the tetramerous 

 tarsus, which seemed to be equal to it, was nevertheless 

 shorter by nearly 4 millim. I was therefore led to conclude 

 that the latter was the only one that formerly had undergone 

 autotomy. 



To explain so trifling a difference in the length of the two 

 limbs and the absolutely similar coloration that they exhibited 

 one had necessarily to suppose that spontaneous amputation 

 had taken place when the insect was still but a larva scarcely 

 emerged from the e.g^. 



In order to assure myself of the fact I collected a certain 

 number of eggs of Monandroytera inuncans and watched 

 them hatch. At birth tlie larvae measure about 1 centim. in 

 length by 1 millim. in breadth. Their colour is a pale yellow, 



