No. 632] CHIASMATYPE AND CROSSING OVEli 195 



amined the phenomena in Orthoptera and other insects. 

 Incidentally I may remark that Janssens cites from one 

 of my own papers ( 12) in support of his general theory 

 and also copies from another ('13) a series of general 

 diagrams by which the theory was illustrated. As he 



points out, these diagrams were too much simplified to 

 give an adequate representation of his views ; but a crit- 

 ical account of cytological minutia was obviously inex- 

 pedient in a presentation intended only to make clear to 

 a general audience the nature of Janssens 's fundamental 

 assumption. I am glad however to see from these latest 



