Results of preciptin tests for anti-human blood and anti-bird blood were shown for 555 T. sordida, captured in inhabited houses in the State of S. Paulo Administrative Regions of Ribeirão Preto and S. José do Rio Preto. Besides getting the hematophilic index of seletivity of Hess, Hayes et Tempelis 9, a device built in order to offer simultaneously human blood (the fore arm of the researcher) and bird blood (the breast of a pigeon) was used. The analysis of the results of preciptin tests, the index of selectivity and the results of the offering of two alternatives as blood sources, showed that the T. sordida has a definite preference for bird blood save on two occasions, when the human source was far more available.
Trypanosomiasis, South American; Triatoma sordida; Triatomids