Unless the NCBI has added new features that I'm unaware of, one cannot
search a subset of the sequence databases.
I was wondering if a fly group has prepared a publicly accessible server
that contains *only* Drosophila sequence data and the BLAST programs.
Optimally, this restricted database would be as up to date as the one at
Laboratory of Genetics
The Rockefeller University
212-327-8233 (-7420 fax)
myersm at rockvax.rockefeller.edu