Tiny Baetis mayflies are perhaps the most commonly encountered and imitated by anglers on all American trout streams due to their great abundance, widespread distribution, and trout-friendly emergence habits.
Source: The first records of Mesocapnia (Plecoptera: Capniidae) from China with description of a new species
Diagnosis and remarks. Mesocapnia variabilis males are macropterous (Fig. 3). The main epiproct sclerite has a distinct swollen bulb near mid-length, narrowing distally and slightly wider before gradually tapering to a point (Figs. 1 – 2, 14).