In two populations of Ceriagrion tenellum, the frequencies of androchrome (typica) and gynochrome (intermedium) female morphs were estimated using capture-recapture methods. The sex ratio (% males) was equal (72-81) in both populations, although the population size and density of males differed (174±32. and 0.53./m² versus 1488±47. and 0.62./m²). In accordance to the population-density hypothesis (Hinnekint, 1987) androchrome females were significantly more abundant in the larger and denser population (39-50% versus 11%). However, the frequency-dependence hypothesis (Robertson, 1985) could also account for these differences. Therefore, future experiments are needed to differentiate between these hypotheses.