The answer is no. They are two different US Military Operation Units.
遊騎兵refers to the U.S. 75th Ranger Regiment —also known as the United States Army Rangers— is a special operations force of the United States Army Special Operations Command (USASOC); with headquarters in Fort Benning, Georgia. The Regiment is a flexible, highly-trained and rapidly deployable Light Infantry force with specialized skills that enables it to be employed against a variety of conventional and special operations targets.
The force specialises in airborne, air assault, Light Infantry and direct action operations, raids, infiltration and exfiltration by air, land or sea, airfield seizure, recovery of personnel and special equipment, and support of general purpose forces (GPF) among others. Each Ranger battalion can deploy anywhere in the world within 18 hours' notice.
Not all Army Rangers could become soldiers of Delta Force. Only soldiers from either Army Rangers or Navy Seals could apply for Delta Force positions.
http://en.wikipedia.org/wiki/Delta_Force#Recruitment_and_training
三角洲部隊 refers to the 1st Special Forces Operational Detachment-Delta (1st SFOD-D), commonly known as Delta within the U.S. Army or as Delta Force by the general public and officially recognized by the Pentagon as the Combat Applications Group, is a Special Operations Force (SOF) and an element of the Joint Special Operations Command (JSOC).
The force's main task is counter-terrorism, although it is extremely versatile. Delta Force is believed to conduct missions similar to those regularly attributed to the British Special Air Service (SAS), after which it was modeled.
Delta Force recruit Army Rangers, Navy Seals and sometimes work along with United States Navy Special Warfare Development Group to carry out special operations.
for more information about Delta Force:
http://en.wikipedia.org/wiki/Delta_Force