AbstractLarval growth rate has the same temperature coefficient in three species of coenagrionids, but Argia vividaand Amphiagrion abbreviatum, which frequently live in geothermally heated water, grow fastest at 29.0–30.0°C compared with 23.4°C for Coenagrion resolutum, which lives in cooler water. Survival below 15°C in the laboratory was much better in C. resolutum.These characteristics are reflected in the distributions of the three species, C. resolutumranging much further north in North America than the other two species, but not penetrating as far south. By contrast, the temperature coefficient for Lestes disjunctusis higher than that of the coenagrionids, and this is related to a different life history. In the coenagrionids, one or more winters are spent in the larval stage. In L. disjunctus, winter is spent in the egg stage, and larval growth must be completed quickly.