21a (20b). Hind wings with anal area nearly always enlarged and forming a lobe, which is folded

like a fan at rest; venation varying from normal to very dense, the front wings usually with

several cross veins between Cu-1 and M and between Cu-1 and Cu-2 (Fig. A); cerci

present and often fairly long; mostly 10 mm or more in length; nymphs aquatic, and adults

usually near water (Figs.A-F) [stoneflies]..........................................................................Plecoptera

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A B C D

E F

21b. Hind wings without an enlarged anal area and not folded at rest; venation normal or

reduced, with no extra cross veins; short cerci present or absent; mostly 10 mm in length

or less; nymphs not aquatic and adults not regularly near water.........................................…....... 22