Protectin from the sponge Aaptos papillata (Keller) was used in the characterization of five strains of T. cruzi (Venezuela, Guatemala, Y. Brasilien, Peru, Wien) and six T. cruzi like strains (Triatoma, Maryland, ITMAP 943, FH4, FH5, LN). Based upon their membrane receptors, these T. cruzi and T. cruzi like isolates could be differentiated from rangeli (Venezuela Strain) and T. conorhini (Hawai Strain) by agglutination reaction to the proctectin. Furthermore, after pronase treatment T.rangeli could also be distinguished from T. conorhini by agglutination test with A. papillata protectin and also Soja hispida lectin. It is not possible to differentiate the T. cruzi complex with S. hispida lectin, because it did not agglutinate T. cruzi (Vienna Strain) and T. cruzi like (Maryland Strain). However, after treating this human pathogenic strain with pronase the pseudocrypt antigen of the first order is made available to the S. hispida lecting thereby producing agglutination. The T. cruzi like strain however did not agglutinate with this treatment. On the other hand, while T. rangeli did not agglutinate even after pronase treatment, T. conorhini showed the agglutination reaction. This observed reaction is explained by the availability of the pseudocrypt antigens of the first order after pronase treatment.