The life cycle of the dragonfly Lanthus vernalis Carle from a mountain stream in South Carolina, United States (Anisoptera: Gomphidae)

A year-long program of qualitative sampling at Howard Creek, Oconee County, South Carolina, yielded data on instar sizes and the pattern of larval growth for L vernalis. Head-width size ranges were determined for the last 7 instars. In the final instar, female larvae were larger than male larvae. No final-instar larvae were collected from the stream from April through June. Apparently no penultimate larvae reached the final instar during the early summer. This gap in occurrence of final instars corresponds to the flight season based on literature records from South and North Carolina. Final-instar larvae present from mid-summer on appear to overwinter rather than emerge. The lack of a clear pattern in larval growth implies a mixed vollinism. It is suggested that L. vernalis is at least semivoltine with the possibility that some larvae take longer to develop in this cool, unproductive stream.