Fig. 2

Comparison of non-swollen versus swollen first metatarsal segments. a, b Non-swollen, Orthophlebia extensa (CNU-MEC-NN2014059). c, d Slightly swollen, Orthophlebia elenae (CNU-MEC-NN2014005). e, f Moderately swollen, Juraphlebia eugeniae (CNU-MEC-NN2014009). g, j Heavily swollen, Mesopanorpa luanpingensis (CNU-MEC-NN2016222). h, i Extremely swollen, O. extensa (CNU-MEC-NN2006046). b, d, f, h, j Habitus, first metatarsal segments of (a, c, e, g, i). Scale bars represent: 4 mm in (a, c, g, h, j); 0.5 mm in (b, d, e, g, i)