Among federal agencies, it might be said, the least favorite piece of incoming mail is the dreaded "Dingellgram."

These little bombs come under the letterhead of the House Energy and Commerce subcommittee on oversight and investigations and over the signature of its chairman, Rep. John D. Dingell (D-Mich.). In between, more often than not, is a request for voluminous piles of documents, telephone logs and memos -- a sure sign that the receiving agency has done something to stir the appetite of Dingell's crack staff lawyers, whose penchant for investigatory detail is legend.

So when a Christmas card signed by Dingell and his wife, Debbie, and addressed to "Administrator William D. Ruckelshaus" arrived at the Environmental Protection Agency last month, the agency grabbed the chance to retaliate.

Linda J. Fisher, executive assistant to Administrator Lee M. Thomas (who took Ruckelshaus' place more than a year ago), fired off a letter complaining about the subcommittee's "grossly and deliberately outdated Christmas card mailing list (CCML)" and demanded answers forthwith to a three-page interrogatory.

Samples:

*"Are you aware that Lee M. Thomas is now the administrator of the Environmental Protection Agency? If not, why not? If so, when did you find out? Who told you? Why did you not update your CCML accordingly?"

*"Provide a full listing of all individuals on your CCML. For each name, provide address, zip code, favorite ice cream flavor, political affiliation, age, shoe size, highest level of education, employer, current salary and ultimate political ambition."

*"Provide a list of all people with whom you have discussed the CCML during the past five years. For each, provide telephone logs, calendars, memos, notes, drafts of all written documentation concerning this list."

*"Provide a list of all individuals not on your CCML."

The letter was dated Dec. 16. On Dec. 19, the subcommittee staff counsel offered a partial response to the last request, promising further documentation "as soon as we obtain permission from the committee on the budget to have thoughts on this matter and then to reduce any such thoughts to writing."

"In accordance with the enforcement-sensitive nature of the enclosed materials," the letter added, "we request that you maintain the confidentiality of these documents."

Enclosed, under separate cover, was a stack of telephone books.