Mary Lopez recalls her son's 22nd birthday without joy. The sun was shining and the spring air crisp in the small town of Globe, Ariz. But she was filled with torment, uncertainty and despair.

"When I realized, my God, it's his birthday, it was a very devasting day for me. I was very depressed," she says. "It's hard to get your spirtis up."

Marine Sgt. James Michael Lopez turned 22 on May 21 -- his 200th day of captivity in Iran.

Now comes another unhappy milestone -- a double one -- for Lopez and the other 52 hostages. It is eight months to the day since their ordeal began with the U.S. Embassy takeover in Tehran. It is also a day commemorating American independence and freedom, normally a celebration of U.S. strength.

At churches and patriotic ceremonies across the country, the July 4 holiday will be observed amid somber reminders of the hostage crisis. "Please do remember them," says a spokesman for FLAG (Family Liaison Action Group), a group formed by the captives' relatives.

For the hostages' families, the special days have come and gone -- birthdays, wedding anniversaries, holidays -- days of bleak remembrance and dashed hopes. As the Iran crisis fades from public attention, some families fear, at times, that their agony may have been forgotten. Some wonder what, if anything, the U.S. government is doing to gain the captives' freedom.

Festive occasions often become times of sorrow."Our 25th wedding anniversary is [this] month, and I still keep hoping they will be out by then," said Dorothea Morefield, wife of U.S. Consul General Richard H. Morefield. "In my heart, I doubt they will be, but I still hope."

Toni Sickmann has appealed to friends and well-wishers to help mark the 23rd birthday of her captive son, Rodney, a Marine sergeant. "It is Rocky's birthday July 26th and they can send cards to him," she said. "People kind of forget [the hostages] and I don't think that they should."

The dearth of mail from the hostages since the aborted April 24 military rescue mission has heightened the families' worries. Previously, letters had offered at least limited assurance that most of the captives were relatively healthy and articulate. Since the military raid, officials say, only nine families have received letters.

"We havent's had one," said Mary Needham, who's hostage son is Air Force Capt. Paul M. Needham. "I wish we had a half a dozen, I really do. I wrote to him last night and I said 'Boy could we use a letter.'"

Only one recent letter is said to provide any apparent corroboration for the Iranian militants' claim that they dispersed the hostages throughout Iran after the aborted rescue attempt.

"I have been out of Tehran for over a month, but not allowed to say where," economics and oil specialist Robert O. Blucker, 52, wrote to his mother, Hazel Albin, in a letter dated June 1. In a telephone interview from North Little Rock, Ark., she said her son appeared to have been moved to northern Iran because he spoke of cooler weather and he noted that buds were not yet on the trees.

Blucker indicated that his treatment has improved. "I was without a bath over three months, but here can take a hot shower every day," he wrote. "And we also get to go outdoors for one to two hours nearly every day. I have a suntan."

But he also mentioned mishaps. "I have been barefoot for several months now and it appears my shoes cannot be located," he said. "I've had all my hair cut off but kept the beard, so you wouldn't know me."

Official U.S. sources say they believe that most of the hostages are within the American Embassy compound in Tehran. Some probably were transported elsewhere immediately after the April 24 military mission, the sources say, but some of these were later returned to the embassy complex.

The few other letters received from hostages in the past two months suggest that their treatment is acceptable and that they are permitted to read, exercise, speak with one another and eat adequate meals, according to serveral hostages' relatives.

The letters do not mention the failed U.S. rescue attempt, they say.

Occasionally there is an oblique hint -- a mention of surrounding or American-style food -- indicating that hostages are still at the embassy compound.

Two private groups that previously arranged to transport letters back and forth between the hostages and their families -- the United Methodist Church and the International Indian Treaty Council -- are currently seeking to revive their humanitarian mail-delivery service.

Some hostages' families also express anxiety because no neutral observer has been allowed to visit the captives since April, when officials of the International Committee of the Red Cross reported seeing all of them.

"If they're well cared for, I don't see why they shouldn't allow people to see them. That concerns me deeply, " said Mrs. Lopez.

Hostages' families express mixed feelings about the reduced U.S. political emphasis and curtailed news coverage of the Iran crisis in recent weeks. Some believe a diplomatic settlement may be hastened if chanting Iranian crowds can no longer be seen on nightly U.S. television broadcasts. iBut some families also worry, especially in moments of despair, that the hostages may be virtually abandoned, left to await the uncertain outcome of murky diplomatic and political maneuvering.

"It gives you the feeling sometimes; 'Do they really care? Are they doing anything?'" said Teresa Gallegos whose captive son is Marine Cpl. William A. Gallegos. "It's been too, too long."

"They're just letting them go to hell over there," said Zane Hall, the father of a hostage, Army Warrant Officer Joseph M. Hall. "There's no doubt in my mind that [President Carter is] doing nothing."

But Barbara Rosen -- whose husband, press attache Barry Rosen, is a hostage -- said she has long favored a toning down of political and diplomatic rhetoric. "It's much better if it's deemphasized and we let the diplomats work," she said.

While Barbara Timm, the mother of Marine Sgt. Kevin J. Hermening, was granted permission by State Department to make her second trip to Tehran, other hostages' families do not appear to be planning similar visits, at least at present.

Timm returned to the United States from Paris late last month without completing her second journey to tehran. Her lawyer, Carl Mcafee, said the trip was thwarted because of restrictions imposed on Timm's travel permit by the State Department.

Previously, the family of another captive, publich affairs officer John E. Graves, had expressed interest in going to Tehran. But Graves' wife, Bonnie, said recently that she had defered any such trip.

"I feel frankly that the situation -- the animosity on both sides -- is at such a high level now that nothing would be useful," she said in a telephone interview. She reiterated her previous call for a congressional investigation of the past U.S. actions in Iran as a step toward ending the crisis.