It is known from eight specimens, all found in China.
Its population is known only from a single, discovered specimen.
It is known only from a single specimen, a male.
It is known from eight specimens, with the most recent collected in 1980.
It is known from only a single specimen, collected in the 1950s.
All but one of the described species are known from fewer than 10 specimens.
It is only known from a single specimen collected and described in 1844.
In 1995, the species was known from only three specimens, but additional information has surfaced since then.
It is extinct and was only ever known from a single specimen.
Originally discovered in 1949, it is known only from a single specimen.