séance du 20 Avril Ì921 (VA 



as long as vviùe, considorod sinpfly. wlicMcas tho cor- 

 rospondinu" joints of the adidt arc on the contrary 

 I wire as broad as Icn^r. 



(>oiisi(!ei'injü" (J ntni. as the leiifxth ol' joints 4-47 

 in Ihe young larva and 11 mm. as approximately 

 the length ol 44 joints formed at a later period, I 

 obtain the following results : 



J(^ints l'i5-178 which correspond in the adult 

 U) the original jciints 4-47 have grown 22.5 minus 

 () = 1().5 mm. Joints 92-135 from the time of tlieir 

 appearance have grown 19.5 minus 11 = 8.5 mm. 

 Joints 48-91 have grown 15 minus 11=4 mm. and 

 finally joints 4-47 formed successively at a few 

 days interval iiave grown perhaps one or two milli 

 metres. 



Adding together Ki.o, 8.5, 4 and 1, we have 

 30 mm. which repr-sents appioximately th.e increase 

 due to growth. 



Thus we see that of the total growth of 6-3.5 mm., 

 30 mm. are due to grow ine of the joints, and the 

 remainder to the formation of new joints. 



These estimates being only approximate, wc may 

 without unduly straining the figures attribute half 

 the increase to the formation of new^ joints and t'-e 

 other half to the growth of individual joint.-» 



Besides the antennae, cc»ckroaches possess two 

 small organs the joints of which also increase in 

 numbei during the postembryonic divcjopnient. 

 These aie the cerei, which are foinid in both sexes 

 whereas the styles occur only in the males. There is, 

 however, a difference between the cerei of the males 



