On Sunday April 24 I went to Tam Dao 2 and walked part of the long trail. It is still early in the season and the morning was misty, so I did not see many species, although I was happy with many Bayadera continentalis, a species I only know from Pia Oac.
But I bumped into what I considered a Megalestes species, hanging inside a small bush. But it had a pale yellow humeral stripe and seemed a little odd. When I caught it I also noticed the rounded appendages, without the thickened apex of the Megalestes species that occur here. I did not notice the slight grayish area distal to the pterostigma or my suspicions would have been roused further. However, when I found another individual a little later, this specimen had distinct half-bands distal of the pterostigmata, something never seen in Megalestes.
At home I could solve the mystery and was happy that I had a new genus for Vietnam: Sinolestes. Originally Needham (1930) described three different species for the genus, but since they have all been synonymized. Now only one species is recognized, variable Sinolestes editus, which sometimes has almost all of the outer wing, apart from the apices, completely dark, but more often a band across the wing behind the pterostigmata, or sometimes even hyaline wings. S. editus occurs in southern China, including Guangdong, Guangxi and Hainan. Maybe it is not surprising it also occurs in Vietnam, but it is a large and conspicuous species, so it likely is not common.
|Sinolestes editus, male. Note the dark bands in the wings. And the appendages that slant upwards.|
|The female also has a distinctive feature. Note the lateral yellow squares on S9.|
|The appendages of the male in dorsal view, nicely rounded|