MEXICAN-AMERICAN STUDENTS FROM 13 GRADE LEVELS WITHIN THE WASCO, CALIFORNIA, PUBLIC SCHOOLS WERE TESTED IN MARCH, 1967, AS PART OF AN EVALUATION OF STRENGTHS AND WEAKNESSES OF RURAL MEXICAN-AMERICAN STUDENTS IN CALIFORNIA. ANALYSIS OF TEST RESULTS REVEALED THAT MEXICAN-AMERICAN STUDENTS FELL PROGRESSIVELY BEHIND IN PERCEPTUAL MOTOR DEVELOPMENT--A DEFICIT ATTRIBUTED TO BOTH HOME AND SCHOOL ENVIRONMENTS. LOW SELF-CONCEPT SCORES AND ABOVE-NORMAL SOCIAL MATURITY SCORES MAY HAVE REFLECTED THE DEMANDS OF 2 CULTURES ON THE MEXICAN-AMERICAN STUDENT. ACADEMIC ACHIEVEMENT PROGRESSIVELY DECLINED, POSSIBLY AS A RESULT OF THE DE-EMPHASIZING OF INDIVIDUALIZED INSTRUCTION AND THE ABSTRACTION DEMANDS MADE ON MEXICAN-AMERICAN STUDENTS BY MATERIALS GEARED TO MIDDLE-CLASS NORMS. TABLES SHOW WHICH TESTS WERE GIVEN TO WHICH GRADE LEVELS, AGE-GRADE RELATIONSHIPS, AND RESULTS BY INDIVIDUAL TEST. RELATED DOCUMENTS ARE RC 002 539 AND RC 001 775. (JEH)