A young Soviet conscript returned recently to his native city of Simferopol to find it "literally flooded with shirts bearing the legend 'U.S. Army' and tags with the American eagle."

Having spent the previous two years in a paratroop unit, Pavel Ribchenko was first startled to see a 19-year-old girl with a patch on her sleeve showing the Stars and Stripes and American eagle. Then he realized that in his absence the city had been practically occupied by young people wearing jeans and T-shirts with inscriptions ranging from "Los Angeles Police Department" to "Boston University."

Just looking around, Ribchenko recalled in a letter to the newspaper Komsomolskaya Pravda, "I was reminded of the existence of the so-called Soviet Institutes, financed by American intelligence."

Things that all Soviet conscripts are taught have led him to conclude that he was in the midst of "psychological war" where the enemy was trying to "enter the subconsciousness" of average Soviet youths and "impose the notion that everything American--the jeans, automobiles, etc.--was the best."

The influx of American jeans and T-shirts results from sales here by foreign tourists, who find the prices paid for their pants too favorable to resist, and by enterprising Russians who bring the goods back from trips abroad.

The alarmed letter was one in a series of articles and comments recently about the sartorial conspiracy threatening to tear the fabric of socialism and apparently requiring Draconian remedies.

One such remedy reportedly was applied in two neighboring Black Sea cities--Nikolaev and Herson-- where young Communist vigilantes, all dressed in proper outfits, swooped down on cafes, dancing halls and parks, rounding up young people dressed in Western clothes and trying to explain the sartorial diversion to which they had succumbed.

The craze for blue jeans and "real labels" has been sweeping the Soviet Union for several years. But in the past weeks, apparently as a result of party calls for greater vigilance following the Polish crisis, the Soviet media have become increasingly critical of symbols of Western life styles.

A doctor of history last month explained to the public just how insidious an attempt was under way to subvert the hearts and minds of Soviet youth.

Also writing in Komsomolskaya Pravda, the main Communist youth organization's newspaper, V. Idayatov endorsed vigilante raids against jeans and T-shirts. But, he said, the raiding parties should attempt tactfully to shame young people into understanding the harm of their sartorial inclinations.

Some emblazoned slogans, he said, are simply hostile to socialism. People often "don't understand the meaning of this or that symbol."

"The eradication of Western symbols is a serious matter," he continued. "It is part of the education of young people to ideological maturity, political understanding, and artistic and aesthetic culture."

The first step in the war against blue jeans and T-shirts, he said, would be to tighten up control in the cities that foreigners visit. The second is to increase control on Westerners who bring such clothes into the country.

Then, he said, the Ministry of Light Industry had better improve Soviet clothes and inject the required sparkle to combat alien elegance. The onus in all of this is on members of Komsomol, the Communist youth organization, who should make their contemporaries ashamed to walk the streets in Western clothes.

There also has been criticism of rock music and Western dancing, which one writer described as being "in most cases something resembling the rituals of a witch doctor."

The tone and volume of criticism appears somewhat harsher than in the past, when the authorities sought to beat the fashion by joining it. The Russians are making blue jeans of their own as well as T-shirts with their own slogans emblazoned on them.

But while Soviet jeans are available at 45 rubles (about $60) a pair, any self-respecting Soviet youth dreams about Levi's or Lee jeans and an American T-shirt.