see MD election law here

Pertinent part of Title 8-710:

(2) If the vacancy occurs during the period beginning 60 days before the regular primary election and ending on the last day of the term, the Governor may:

(i) decline to issue a proclamation; and

(ii) allow the office to remain vacant for the remainder of the term.

60 days before the regular primary would have been back in Dec 07; I believe the last day of the term is Jan 3 2009; so this vacancy would definitely be "during the period". I don't know how much significance to attach to the "may" language.

If it really does give the gov discretion, he must issue a proclamation within 10 days of the vacancy, announcing a

special primary election shall be held on a Tuesday that is at least 36 days after the date of the proclamation

and a

special general election shall be held on a Tuesday that is at least 36 days after the date of the special primary election

If Wynn bails in June, that would put the special primary some time in July, and the special general into August or later. Doesn't seem likely.