This is a male Ixodes ricinus tick (smaller) shown copulating with a female tick (larger).

I. ricinus, the “castor bean” tick, so called because of its resemblance to the castor bean, is a vector for the B. burgdorferi spirochete, the cause of Lyme disease, and is commonly found on farm animals, and deer who are the natural host.

Picture & text from CDC/PHIL. For more information on source & for information on color coding used above for different types of ticks, see Tick Pictures from CDC