There has been disagreement concerning the number and identity of the abdominal segments involved in the development of the genitalia and, therefore, pregenitalia of the Hemiptera. Although these studies have been conducted during the past two centuries, they have involved only adults. Here we present the results of our study of the nymphs of Corimelaena incognita (McAtee and Malloch) in which we trace the development of the abdomen through the five instars into the adult and determine the number of segments involved in genitalic development. The total number of spiracles (seven) and location of each spiracle (i.e., below or within the lateral carina) were important in this determination. We conclude that the genitalia begin with segment 9 in the male (pygophore) and segment 8 (gonocoxae 1) in the female.