Electrophilic addition mesomeric effect

A very similar situation is encountered in the electrophilic addition of unsymmetrical adducts (e.g. HBr) to vinyl halides (e.g. CH2=CHBr), where the inductive effect of halogen controls the rate, but relative mesomeric stabilisation of the carbocationic intermediate controls the orientation, of addition (p. 185). 

Now we will turn our attention to the case of a mesomeric group, Z, which is capable of donating a lone pair of electrons into the ring. As before, there are three possible positions of attack for the incoming electrophile. In addition to the nine canonical structures that were considered for the inductive substituent, there is now an extra canonical structure for both the ortho and para substituted Wheland intermediates. Write down these two extra canonical forms, and suggest what effect they will have on the product distribution. 

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