Examination of haemolymph from triatomine-bugs (Triatoma infestans and Dipetalogaster maxima) harboring Trypanosoma cruzi infection for 10, 15, 20 and 30days did not reveal the presence of flagellates. Material obtained by washing out the haemocoel of infected D. maximus was also negative. Inoculation of bloodstream trypomastigotes and triatomine intestinal flagellates into the haemocoel revealed that parasites were not able to maintain a detectable infection in the haemolymph for more than 40 days and that parasites could not enter in the intestine of triatomines. Inoculation of haemolymph of infected bugs in baby-mice has not induced infection.