Ixodes scapularis, Black-legged tick, is a hard-bodied tick from the Ixodidae family. Ix. scapularis is the primary vector for Lyme disease transmitting the pathogenic bacterium Borrelia burgdorfei.
Ixodes ticks also can transmit Ehrlichia, a gram-negative obligate intracellular bacteria that is responsible for Ehrlichiosis.
Ticks that transmit Borrelia burgdorferi to humans can also carry and transmit several other parasites, such as Theileria microti and Anaplasma phagocytophilum, which cause the diseases babesiosis and human granulocytic anaplasmosis, respectively.
From Wikipedia: Ixodes scapularis is commonly known as the deer tick or blacklegged tick (although some people reserve the latter term for Ixodes pacificus, which is found on the West Coast of the USA), and in some parts of the USA as the bear tick. It is a hard-bodied tick (family Ixodidae) of the eastern and northern Midwestern United States. It is a vector for several diseases of animals, including humans (Lyme disease, babesiosis, anaplasmosis, etc) and is known as the deer tick due to its habit of parasitizing the white-tailed deer.