Answer: Ixodes scapularis tick (a.k.a. deer tick, black-legged tick), female, not engorged. Mouthparts are intact. Congratulations to everyone who wrote in - you all had the correct answer.
The answer to the second question I posed, "What would be your advice to this physician?" is a bit trickier. Thank you for all of the thoughtful responses to this post.
In advising physicians about prophylaxis or treatment for tick borne illnesses, I refer to the Infectious Diseases Society of America (IDSA) guidelines (Wormser et al., CID 2006) which state that "for prevention of Lyme disease after a recognized tick bite, routine use of antimicrobial prophylaxis or serologic testing is not recommended." Instead, a single dose of doxycycline may be given for prophylaxis in certain cases; cases should meet the following criteria:
1. Patient is >/= 8 years of age
2. The attached tick is identified as I. scapularis (hence the utility of laboratory identification)
3. The tick is estimated to have been attached for >/= 36 hours (based on degree of engorgement or patient exposure history)
4. Prophylaxis can be started within 72 h of the time that the tick was removed
5. Ecologic information indicates that the local rate of infection of these ticks with B. burgdorferi >/= 20%
6. Doxycycline is not contraindicated
Prophylaxis for other tick-borne diseases (e.g. anaplasmosis, babesiosis) is not recommended.
In this case, the tick is clearly not engorged and was reported to be atached for only 6 hours. Therefore, I advised the patient (in this case, a physician) to not take any further steps at this point, but to watch for signs and symptoms of tick-borne illness such as rash, myalgias, headache and fever, and to see his physician if any of these arise.