HanitscH: Blattldae front the Buitenzorg Museum. 221 



Postcriptum. I regret that only after having written the above lines I 

 came across a paper on asymmetry in the elytra of fossil Cockroaches by 

 Fernand Meunier, viz: 



"L'asymétrie frequente des élytres de Blattidae du terrain houiller de 

 Commentry (Allier) et la phylogénie des groupes", in Comptes rendus 

 hebdomaires des Séances de TAcadémie des Sciences, Vol. CLVI, pp. 493— 

 496 (1913). 



The author states that asymmetry is common amongst fossil Proto- 

 blattinae, Mylacrinae and Blattinae, all of which represent a very archaic type. 

 However, the asymmetry is only a secondary one. it does not modify the 

 disposition of the subcostal, radial, median, cubital and anal veins which 

 invariably show great constancy in structure. It is otherwise with the bran- 

 ches which arise from these principal veins. They always present appreciable 

 modifications. For instance, the number of venules springing from the 

 subcostal may be unequal in the two elytra, i. e. there may be 8 venules 

 in the left elytron, and 10 in the right, or vice versa. Similar variations 

 may take place in the venules coming from the other sectors (radial, median, 

 cubital), and also in the anal field. 



In conclusion the author warns against the habit of establishing new 

 genera and new species founded upon a single elytron only. 



Oxford, February 1922. 



