The number of days that blood meal antigens remained serologically detectable following single and double feedings from known host sources was determined for all nymphal instars and adults of TRIATOMA BARBERI using the capillary precipitin test technique. Antigens of a single blood meal from rat were identifiable 15 to 95 days, with the maximum period of antigen detection occurring in unmolted 5th-instar nymphs. For all nymphal instars, blood meal antigens remained identifiable 2 to 47 days following the molting period. For bugs offered 2 blood meals from different hosts, the 2nd blood meal from chicken increased the maximum period of antigen detection for the 1st blood meal from rat by 15 to 65 days. This "booster effect" of multiple feeding on the duration of blood meal identification resulted in detectable antigens to rat after 2 successive molting periods in instars 2 through 4. Blood meal antigens from the 2nd feeding on chicken were not detectable as long as antigens from the 1st blood meal on rat. However, antigens from chicken were identifiable longer as part of a multiple host blood meal than antigens from rat, where rat was the only blood meal source offered. Multiple feeding increased successful identification of mixed blood meals in T. barberi by boosting the period of time in which component blood meal antigens remained serologically identifiable. Inglés