Séance du W Avril 1921 59 



uï Trnriiles by their size and by a lar greater number 

 of joints. Tlius the (liricrcnce between the antennae 

 of the a(hill and oi' the neuly haieheil larva is far 

 M^ore strikinii". 



I brout(ht back from Ceylon two newly hatched 

 luah' eockroaehes 0-> '. Ih<'\ were ')J) nun. Ioni:, slil! 

 ronipletely white and mounted in Canada balsam ; m 

 bolli eases the number of joints in the antennae was 

 forty seven. 



Eleven other very youn^r males, only two or 

 three days old, but already brown and from 5.5 to 6 

 mm. loniü:, had in one case /47, in another 49 and in 

 lljc rcmainins;- nine cases f\8 joints- For the adults of 

 ilie same species, P. americana, preserved in alcohol, 

 the maxima observed are 172 for the female and 178 

 for the male. As the antennae of the a^^Iults are fre 

 quently damaged, I is'wç only the largest figures. 



In «The Structure and Life-History of the Cock- 

 roach », 1886, p. 4o, Mi.\LL and Denny speaking- of P. 

 Orientalis state that the number of antennal joints 

 varies from 75 to 90 and that the antennae of the male 

 are a little longer while those of the female are a lit- 

 tle shorter than the body. 



In the male specimen of ajricricaria in which I 

 counted 178 joints, the length of the antenna was 7 

 cm. or exactly twice the length of the body. The 

 length of the antenna of a two da\ old male, 6 mm. 



2. The male cockroach is distinguished hy the insertion 

 of two styles on the posterior edge of the last sternum of 

 the al)donien in addition to the cerei présent in both se.xe«; 

 on the last tergum. 



