One of the general defining characters of the Heteroptera is the presence of exocrine scent glands. Previously unknown from the prothorax, exocrine glands are generally associated with the metapleura and abdomen. Using both light and scanning electron microscopy, we found evidence for a previously unrecorded exocrine gland, which we refer to as the pronotal gland. In all examined members of the Collartidini and Ploiariolini (Heteroptera: Reduviidae: Emesinae) and the Saicinae (Heteroptera: Reduviidae), we have found the presence of this gland. Such evidence was not found in other examined tribes of the Emesinae. The implications of this novel complex character on the taxonomy of the Emesinae and Saicinae are discussed.