The emergence period of Ischnura verticalis from a pond in S Ontario lasted at least 97 days; the sex ratio of emerging larvae was not significantly different from 1:1. The life cycle was univoltine and male larvae tended to develop faster than female larvae. Analysis of instar distributions of larval I. verticalis collected from a series of ponds also indicated that males were in more advanced instars than females. Male larvae in the antepenultimate instar consistently spend more time moving and crawled farther than female larvae in the antepenultimate instar. -from Authors

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Journal Canadian Journal of Zoology
Baker, R.L., Forbes, M, & Proctor, H.C. (1992). Sexual differences in development and behaviour of larval Ischnura verticalis (Odonata: Coenagrionidae). Canadian Journal of Zoology, 70(6), 1161–1165.