24-72: Life expectancy in hours of mayflies, after the nymph stage

1-2: Years nymphs live underwater

0.5-3: Length in inches of a mayfly’s body

5: Minutes it takes a typical mayfly to molt or shed

3: Number of tails a nymph typically has

Sources: www.johnbob.net/john/june.html; www.bugsurvey.nsw.gov.au