The egg and the five instars of Sigara (Tropocorixa) schadei (Hungerford) are described and illustrated for the first time. The eggs of Sigara have a very short, basal stalk. The egg of S. schadei has protuberances delimiting small areas on the chorionic surface. The main characters separating the five instars of S. schadei are: the body length and body, head and eye widths; the number of transverse sulcations of the rostrum; the number of setae on the inner surface of the protibiotarsus; the number of long, slender setae on posterior and posterodorsal surfaces of the mesotibia and mesotarsus, respectively; the number of spines on posteroventral surface of the mesotibia; the number of campaniform sensilla on posterior surface of the metatrochanter; the number of spines and swimming hairs on anteroventral and posterodorsal surfaces of the metatarsus, respectively; and the grade of development of the wing pads. Some characters distinguish species or group of species in nymphs of the genus Sigara: the chaetotaxy of the urosternites (instar I); the body length, chaetotaxy of the mesonotum, and number of spines on posteroventral surface of the metafemur, and on posterior and posterodorsal surfaces of the metatibia (instar V).

The immature stages of Sigara santiagiensis are described and illustrated for the first time. The eggs of Sigara can be distinguished by the chorionic surface. The main characters separating the five nymphal instars of S. santiagiensis are: body and head lengths; body, head and eye widths; ocular index; numbers of transverse sulcations of the rostrum, setae on the inner surface of protibiotarsus, campaniform sensilla on posterior surface of protrochanter, spines on posteroventral surface of mesotibia and on tibial comb of metaleg, long, slender setae on posterodorsal surface of mesotarsus, spines and swimming hairs on anteroventral and posterodorsal surfaces of metatarsus; and grade of development of the wing pads. The body length, the chaetotaxy of the mesonotum, profemora and metafemora, protibiotarsus, metatibia, metatarsus and urosternites distinguish species or group of species of instars I and V of some of the species of the genus Sigara described up to now.

The egg and the five nymphal instars of Ectemnostega (Ectemnostegella) stridulata are described and illustrated for the first time, with emphasis on the morphometry and chaetotaxy of selected structures. Comparison with the eggs of E. (Ectemnostegella) montana and E. (Ectemnostegella) peruana, and the nymphs of E. montana and E. (Ectemnostega) quadrata, are included. The egg of E. stridulata has a very short stalk like those of E. montana and E. peruana, and the three species differ in the chorionic structure. The nymphs of Ectemnostega share the presence of one dorsal abdominal scent gland on each of the segments IV–V. The number of spines on the profemur on the ventral and posteroventral surfaces distinguishes the nymphs of the subgenus Ectemnostega from the those of the subgenus Ectemnostegella. The nymphal characters most useful in identifying instars I–V of Ectemnostega are: the body length, the number of spines on the posteroventral surface of the mesofemur, setae on the posterodorsal surface and spines on the posteroventral surface of the mesotibia, setae on the posterodorsal surface of the mesotarsus, and the grade of development of the wing pads. The nymphal characters most useful in identifying species of Ectemnostega are: the number of spines on the posteroventral surface of the mesofemur, spines on the anterodorsal surface of the metatibia, and spines and swimming hairs on the anteroventral and posterodorsal surfaces of the metatarsus.