A new species of the oliveirai complex (new designation for matogrossensis(complex) from the State of Rio Grande do Sul, Brazil

The authors describe a new species of Triatominae (Hemiptera, Reduviidae) f rom the State of Rio Grande do Sul, Brazil. The study was made with specime ns captured in basaltic formations, at an average altitude of 750 m.o.s.l. The new species is included in the oliveirai complex together with other fo ur species T. williami, T. matogrossensis, T. guazu and T. jurbergi). The n ew species was compared with the most similar one, T. oliveirai, from which the main differences are on the proportions of head, and the and postocula r regions, the general color pattern and the male genitalia, specially on t he median process of the pygophore, the support of phallosome, the vesica a nd the process of the endosome.