The Lance-tipped is able to regulate its body temperature (both by shivering and by retaining heat in its abdomen produced in the thorax by its flying) which enables it to fly in temperatures too cold for most dragonflies. Thanks to Scott King for help with identifying this critter.
During last month's heat, Erika and I strolled in the Carleton College Arboretum. As we walked, we kicked up many Common Green Darners. (I wrote about this dragonfly on 6 August 2010.) On this 90 degree day, the darners were regulating their body temperatures by resting in the shade of the bushes and under the leaves along the trail.