IT HAS BEEN quite a month for the FBI. Between Feb. 3, when the Abscam operation made its first headlines, and March 3, when the latest defecting spy was unveiled, the bureau managed to be in the news almost every day. The most recent of its chest-thumping srories offered the silhouette (complete with pipe) of Col. Rudolph Albert Herrmann, said to be a bagged KGB agent.

The whole show, reminiscent of one of those congressional hearings where the witness has a paper bag over his head to protect his identity, seemed to us stagey, hokey, melodramatic and anticlimactic -- in other words, something that trivialized the lagrger KGB effort, not something that made people aware of either its seriousness or its size.

As the last of the month-long series of disclosures, the Herrmann case rounds out the picture of an FBI hard at work. There were its investigations of political corruption, both federal (Abscam) and state (Brilab). There was the crackdown on a national pornography ring (54 arrests). There was the leak concerning an investigation into ties between organized crime and the gambling casinos in Las Vegas. There was the released document revealing the "old" bureau's tolerance of violence by its informers against civil rights workers. There was the resigning official's allusion to five caught and expelled spying diplomats. And now there is this scene from its war against the KGB.

Why all this has come pouring forth within the space of a single month is not clear. Coincidence? Perhaps -- investigations do come to an end, sometimes unexpectedly. Budget time? The late J. Edgar Hoover was a genius at focusing attention on the bureau when it wanted something. Time to embarrass the Soviet Union by "uncovering" one of its agents? Time to stir up Americans over the menace of the Reds? Or merely time to demonstrate that the FBI is back at the old stand after the period of confusion prompted by Mr. Hoover's death and the disciplining of some of its top leaders for authorizing black-bag jobs and other illegal investigations?

Who knows? The one thing of which we are certain is that if -- as some suggest -- this image-making burst is regarded by people at the bureau as a way of proving it is more open, accessible, on the record and up front -- well, forget it.