The Collaborative International Dictionary of English v.0.48:

Sembling \Sem"bling\, n. [Cf. Assemble.] (Zool.)
   The practice of attracting the males of Lepidoptera or other
   insects by exposing the female confined in a cage.
   [1913 Webster]

   Note: It is often adopted by collectors in order to procure
         specimens of rare species.
         [1913 Webster]