BY GAIL EPSTEIN NIEVES

 Cuba's foreign intelligence agency devotes an entire department to infiltrating exile
 groups and another department to getting inside the FBI, CIA, State Department
 and other U.S. governmental agencies, an expert in Cuban spy matters testified
 Thursday.

 Stuart Hoyt Jr., a retired FBI agent, unraveled the hierarchy of Cuba's intelligence
 services from ``Commander in Chief'' Fidel Castro on down. His testimony
 provided some context for jurors in the Cuban spy trial, who every day read or
 hear another acronym related to Cuban intelligence.

 None of the jurors is Cuban- American, so they probably would not be expected
 to know that the Directorate of Intelligence, or DI, is Cuba's main foreign
 espionage agency.

 Within the DI are eight departments, all of which start with the letter M followed by
 a Roman numeral, said Hoyt, who retired from the FBI in 1994 after 24 years of
 foreign counter-intelligence work, first against the Soviet Union and later against
 Cuba.

 Hoyt was assigned to field offices in New York, Boston, San Juan and
 Washington, D.C., and for three years he supervised the agency's anti-Cuba
 efforts. He still works under contract with the FBI.

 Hoyt named the intelligence departments as follows:

   MX is the office of the DI's chief, Brig. Gen. Eduardo Delgado Rodriguez.

 The indictment in this case used the code ``MX'' for the Havana chief who directed
 the accused spies to gather information that allegedly helped Cuban MiG
 warplanes shoot down and kill four Brothers to the Rescue pilots in 1996.

   MI is responsible for infiltrating U.S. government agencies.

   MIII collects and analyzes all information coming into the DI.

   MV supports ``illegal'' intelligence officers, or those who enter the U.S. illegally.

 ``Legal officers'' arrive legally and operate in official diplomatic missions, including
 M15, the Cuban mission to the United Nations in New York City; M2, the Cuban
 embassy in Mexico City; and M6, the Cuban embassy in Madrid.

   MIX is ``active measures,'' which refer to the use of disinformation, threats and
 violence to discredit enemies or otherwise influence someone's actions.

   MXI monitors phone calls and airplane radio communications.

   MXV handles communications between Havana and agents in the United
 States.

   MXIX infiltrates ``counter-revolutionary'' Cuban exile groups that oppose the
 Castro regime. Cuba has another group with a name similar to the DI but with a
 very different function. The Directorate of Counter Intelligence, called CI, works
 within Cuba handling ``internal control to ensure people don't speak out against
 the government,'' Hoyt said.

 Both the DI and the CI are part of the Ministry of the Interior, MINIT, one of the two
 most powerful ministries, or departments, in the Cuban government. The second
 is the Ministry of the Revolutionary Armed Forces, MINFAR, or the Cuban
 military, Hoyt said.

 The five men on trial are accused of spying for Cuba as part of La Red Avispa, the
 Wasp Network, whose members allegedly tried to penetrate U.S. military
 installations and Cuban exile groups.

 Hoyt said the network used typical spying techniques, including writing secrets
 on water-soluble paper that could quickly be destroyed. Jurors saw four such
 papers.

 The network also used ``compartmentalization,'' or limiting each person's
 knowledge, so that ``in case one is arrested, he will not be able to identify the
 other.''

 The accused spies also communicated with beepers and pay phones, used
 counter-surveillance measures, post office boxes, fake documents and
 concealment devices, he said.