The authors observed the feeding and defecation times of the nymphs of T. melanosoma Martínez, Olmedo & Carcavallo, 1987. Two groups were studied, one maintained under controlled conditions of temperature and humidity, and the other under ambient conditions. There was no significant difference in the number of bloodmeals accomplished by the nymphs of the two groups. Until the fourth instar the nymphs needed less than two bloodmeals to reach the subsequent instar, and only in the fifth instar did they require more than three bloodmeals to reach adulthood. This species demonstrated great avidity to feed; in about 70% of the observed cases the insects initiated feeding in less than one minute. Full engorgement was also reached quickly; more than 70% of the bloodmeals lasted for 5 to 15 minutes. In the first three instars more than 70% of defecation was observed immediately after feeding, demonstrating a good vectorial potential. The differences in the conditions under which the insects were maintained, were insufficient to cause a significant difference in the results observed between the two groups studied.