The midterm crunch always sneaks up on us. Whether it means we're writing reams of pedantic essays or botching hundreds of exams, chances are good that this week has brought almost every Harvard undergraduate to the precipice of academic catastrophe--or at the very least, to the precipice of the dreaded B-plus. But we often forget that it is actually the week after midterms, not the midterm week itself, that is crucial to our academic success. Next week, our papers and midterms will come back to us graded. And right now, our fate is entirely in the hands of one individual: the teaching fellow.

"Teaching fellows." Who are they really? Through a rigorous study of TFs in at least 25 Core classes, I and my colleagues at the Institute for the Study of Teaching Fellows and Prokaryotic Life have conclusively determined several facts about the life cycle of the common TF. In the larval stage, young TFs-to-be squirm through high schools nationwide, leaving oozing trails of teacher recommendations and bibliographic references in their wakes. Pupating during their undergraduate years, many emerge from their pre-university cocoons as some version of that smarmy first-year in your section who always does the reading and asks if he or she can hand his or her paper in early. After this adolescent phase (often marked by the growth of a large, tumor-like "thesis"), spawning begins, and we find colonies of proto-TFs developing in warm, dark places such as Loker and the Gato Rojo Cafe. Thriving on response papers and underused undergraduate brain cells, TFs have become one of the most populous species at the University.

There are countless breeds of TFs, and many (including mine, of course) manage to rise above their larval roots to become great instructors and, hopefully someday, great professors. But others, through either intense training or abnormal mutation, distort into a subspecies taxonomically known as Bad TF-hood--that is, one to look out for after handing in that paper. Because Bad TF-hood is a highly developed and cultivated state requiring great tenacity to achieve, we at the Institute have developed the following manual, originally published in the New England Journal of Semiotic Hermeneutics of Lower Academic Ecosystems, designed to guide up-and-coming undergraduate and graduate students into a world with no natural predators. Somewhere in this College, someone is preparing to become a Bad TF. It might even be you. So read on!

Part I: Sections are a crucial part of a student's education. Not all sections are equal. Some will be filled with enthusiastic future TFs who can't keep their mouths shut, while others will merely have two such students who shield the others from your attack. Don't fall for this ruse. Use the following tips to make the most of your fifty minutes of fame:

1) Call on people by name. This may require having students make little signs with their names on them to wear on their foreheads, or it may merely require you to address students by arbitrarily chosen syllables. The guy with the brown hair and glasses is Joe. Really.

2) Every student must be encouraged to participate in section. This can be a frustrating task, but persistence is the key to success. For example, imagine that in a section beginning at 1 p.m., you ask Joe a question at 1:12 p.m. From Joe's incoherent grunts, it is immediately clear that not only has he not done the reading but may indeed be completely unaware of what the reading was, or that reading was actually assigned. Do not be discouraged. Call on Joe again at 1:23 p.m. Then try again at 1:34, then again at 1:45 and 1:53. You never know when he might suddenly decide to be prepared.

3) For out-of-class contact, do not, under any circumstances, learn how to use e-mail. It is important, however, to collect student e-mail addresses and occasionally send out a notice that says, "Just wanted to remind you that section time has been changed to 7 a.m.," thus deceiving students into thinking that you have a functioning e-mail account. Once or twice during the semester, a student might ask you whether you received an e-mail message from them. Don't be fooled. The answer is always no.

Part II: Evaluating midterms and papers is the most important part of the TF's identity. Paper evaluation separates the ordinary TF from the Bad TF, the mere dabbler from the seasoned pro. Some key points to remember:

1) Vividness and clarity are crucial to commenting on papers. When grading a student's paper, be sure to use only green, pink, purple or orange ink.

2)Attention to detail is especially important. Approximately every page-and-a-half, find an adjective or adverb. Underline it twice, draw an arrow to it, and write "Really?" Then, underline every twelfth line and place a question mark in the margin.

3) Comments should be short and to the point. For example, you might choose to draw a short vertical line alongside about half a paragraph of the student's paper. Next to it, write "Awk."

Part III: Nothing is more crucial at the end of the paper or exam than actually assigning a grade. Some TFs choose to assign grades arbitrarily, an atavism which dates back to a primitive TF life cycle in which TF pupas, scattered to hostile environments by lack of grant money, would randomly mutate into either TFs or financial consultants. While this approach is encouraged, a finely tuned Bad TF can grade papers with a combination of whimsy and style. At the end of the paper or exam, write "Nice Work." Below that, write "B+." Then, in a different-colored pencil, cross out the "B+," and write "B."

Half-student and half-teacher, TFs can sense fear and are often dangerous when threatened. Some have even been known to hurl their harshest self-defense--the "B-minus"--when attacked. However, those who study the species have recognized that while hostility may increase during midterm week, TFs are actually very gentle, docile creatures, easily placated by a visit to office hours or even the simplest intelligent comment in section. Take care of your TFs. Feed them response papers regularly and hand them your midterms with a smile. And then someday, when you yourself pupate, you may find that you, too, will rise through the academic food chain.

Dara Horn's column appears on alternate Fridays.