Perplexed

I've just got one question this morning. How with the antiseptic atmosphere of these hotels lacking operable windows, congested with intervening lobbies separating you and the outside, do mosquitos get into my room? I see them gathering outside my window this morning; that I can take. But last night when I surprisingly discovered what I thought was a solo transgressor and smeared him against the vinyl wallpaper, I assumed that was it. Not so. Morning greetings at six am, buzzing in the ear. Could they be living in the air conditioning system?