Common flangetail (Ictinogomphus pertinax, 霸王叶春蜓).
From the lily pond at Xianjia Lake (咸嘉湖). With its stripes and glaive-like tail, it is my favourite local dragonfly; they are common here in the summer, and they frequent the edges of still
waters, which is convenient for close observation. If they are more pertinacious (pertinax) than other dragonflies, I have not noticed.