903 



1897.] ON HEGENEEATION OV THE LEGS IN THE BLATTIDiE. 



wounds and other iajuries, that Mr. Holding thought the specimen 

 exhibited was of some interest as indicating that organic disease 

 might also be a factor in the degeneration of horns. 



The following papers were read : — 



1. On the Regeneration of the Legs in the Blattidce. 

 By H. H. Bkindley, M.A., St. John's College, Cambridge'. 



[Received September 13, 1897-] 



In 1892 Mr. Bateson called my attention to the fact that 

 specimens of the common Cockroach {Stylopyga orientalis) are 

 not unfrequently found to exhibit an abnormal condition of the 

 tarsus, or distal portion of one or more of the walking-kgs. 

 This abnormal condition is a numerical variation of the tarsal 

 joints, only four being present instead of the normal number, 

 five — the tarsus as a whole, however, presenting in other respects 

 the features proper to the five-jointed or normal condition. 

 Mr. Bateson suggested to me that it might be M'orth -while to 

 investigate in detail this instance of meristic variation. 



The particular interest of the case was that the inspection of 

 four-jointed tarsi in a few individuals seemed to point to the 

 conclusion that the relative proportions of the several joints 

 therein were constant. This abnormal tarsus seemed to possess a 

 fixity or organic stability of structure such as is held usually to be 

 the outcome of the continued operation of selection, an influence 

 which can hardly be called upon to account for the condition of 

 an occasional abnormality. 



The investigation thus originated called attention to facts other 

 than those bearing directly on the original question concerning 

 which infoi'mation was sought. The latter have been discussed by 

 Mr. Bateson in his work on Variation ". I postpone reference to 

 his conclusions till an account has been given of the observations 

 made before and after his book was pubhshed. The present paper 

 is concerned chiefly with certain facts regarding the reproduction 

 of lost or injured legs in the Blattidte, and with some points in the 

 post-embryonic development of Styhpyr/a orientalis. 



The former of these two subjects cannot be considered apart 

 from that of the reproduction of parts among other Insecta and 

 the Arthropoda as a whole. It has therefore seemed more 

 satisfactory to describe separately the results of the obsei-vations and 

 experiments originally undertaken for a more circumscribed purpose, 

 leaving the details of reproduction to a future communication. 



The leg of the Cockroach resembles that of other Orthoptera, 

 and consists of the following parts : a massive coxa, which is 

 movably articulated with a small trochanter, to which latter is 

 immovably fused a stout femur. The parts distal to the femur 

 are the tibia and tarsus, all of whose articulations are movable. 



1 Communicated by W. Bateson, M.A., F.R.S., F.Z.S. 



■^ • Materiiila fur tlie Study of Variation,' 1894, pp. 63 & 415. 



