Which Insect Bite Leaves Black Scars On Legs?

Hi, may I answer your health queries right now ? Please type your query here...I just got from a week long trip to the Yucatan Peninsula, Merida and Cancun, on the last day i went Zip lining but it was late at night, later that night i notice bug bites i thought they were black gnat bites and would be gone later it has been a week and they bites are still here and i keep finding more, they are only on my calves and my forearm, what type of bug bites are these?