In an inexplicable flight of literary fancy, White House press secretary Jody Powell reached back through 26 centuries yesterday for an explanation of President Carter's energy policies.

Powell chose as his text the story of "The Ant and Grasshopper," one of the fables attributed to Aesop, the famed storyteller who lived as a slave on the island of Samos in the sixth century B.C.

But while Powell clearly meant to suggest that Carter's critics are as irresponsible as the grasshopper in the story, it is doubtful that he actually consulted the fable's description of the ant before comparing the president with the insect.

If he had, he would have noted that the ant is described as "rich [and] purse-proud," a hoarder of "vast bonded warehouses of corn" who dismissed a plea for food from the starving grasshopper "with unpardonable callousness."

That, of course, is not what came through in the version offered by Powell yesterday during his regular news briefing. Instead, he portrayed the president as ant-industrious and blessed with foresight-and contrasted him to his flighty grasshopper critics.

"There was a grasshopper and an ant and the ant was a drudge and worked hard" Powell said. "And a lot of people said the ant didn't make speeches with a lot of rhetroic in them. The ant was very studious, worked very hard and spent all his time trying to stockpile food for the winter, because he knew there were bad times ahead."

The grasshopper, in contrast, "spent all spring and summer fiddling, chirping, having a good time and generally poking fun and making irresponsible statements about what the ant was trying to do," Powell said.

But the day of reckoning finally came, the press secretary continued, a gleam in his eye. That happened in winter when the grasshopper, desperate for food, admitted to the ant that he had made "a serious mistake" and asked the ant to share "a little food."

"And the ant said, 'Kiss off,' and the grasshopper died," Powell said.

Powell never identified the grasshopper in his version of the fable, although he clearly intended it to apply to energy-policy critics such as Sen. Edward M. Kennedy (D-Mass).

In a translation of the table by Charles H. Bennett, the ant is portrayed like this:

As a rich, purse-proud ant was airing himself at the foot of an old tree beneath the roots of which lay his vast bonded warehouse of corn, up came a poor starving grasshopper to solicit a grain of barley.The selfish and told him he should have labored in summer if he would not have wanted in winter.

"'But,' said the poor chirper, 'I was not idle: I sung out the whole season. I did my best to amuse you and your fellow husbandmen while you were getting in your harvest.'

"'If this is the case,' returned the ant with unpardonable callousness, 'you may make a merry year of it and dance in winter to the tune you sang in summer.'"

The moral of the story, according to Aesop, is that "as the world dispenses its payments, it is decreed that the poet who sings for his breakfast shall whistle for his dinner." It is not known whether the storyteller would have thought the same lesson would be applied to presidential press secretaries. CAPTION: Illustration, no caption, By Robin Jareaux-The Washington Post