Sensilla associated with the rostrum of eight species of triatominae.

Scanning electron microscopy (SEM) permits description of 10 types of rostral sensilla of eight species of Triatominae. The chaetica sensilla are the most abundant over all the rostral surface. On the second and third rostral segments, these sensilla are arranged in six columns along the main axis. A distinctive sensory field lies on the third segment very close to the emergence of the stylet. The total number of chaetica sensilla increases significantly on the last segment. The number and distribution of sensilla do not differ between nymphs and adults. The pattern of rostral sensilla of five species--Triatoma sordida, T. platensis, T. protracta, T. infestans, and T. guasayana--were analyzed, and the results were compared by multivariate discriminant analysis. Interspecific variability was found. The method is proposed as a taxonomic tool.