  We propose a theory for the new maximum recently observed by Willett et al
[1] in the longitudinal magnetoresistance of a weakly modulated two-dimensional
electron gas (2DEG) near filling factor \nu =1/2 for the current driven along
the modulation lines. The maximum is superimposed upon a new resonance
structure. This occurs due to the geometric resonance of composite fermion
cyclotron orbits with the period of modulation of the effective magnetic field.
We propose here a semiquantitative theory of the dc magnetotransport in a
modulated 2DEG near one half filling. Our analysis is based on the Boltzmann
transport equation and it enables us to obtain this maximum which was neither
observed nor predicted previously.
