  It is pointed out that the wave equations for any upper-lower one-index
twistor fields which take place in the frameworks of the Infeld-van der Waerden
{\gamma}{\epsilon}-formalisms must be formally the same. The only reason for
the occurrence of this result seems to be directly related to the fact that the
spinor translation of the traditional conformal Killing equation yields twistor
equations of the same form. It thus appears that the conventional torsionless
devices for keeping track in the {\gamma}-formalism of valences of spinor
differential configurations turn out not to be useful for sorting out the
typical patterns of the equations at issue.
