Any time you need to match 2 fields use the "AND" statement
Dim  SQL as string
SQL = "Select * From YourTable Where Somefield = '" & Me!Text1 & "' AND SomeOtherfield = '" & Me!Text2 & "';"

Note Me!Text1 is a text box on your form where they are keying in "genus" or whatever. Me!Text2 is for "specie"

What do you want to return when you find the values?
The results in a subform?

then it would be
 Me![YOURsubform].Form.RecordSource = SQL

DougP
dposton@universal1.com

Ask me how Bar-codes can help you be more productive.

he wants the value placed into the form where the person is choosing the genus and specie values from the list box.

Hope you understand what I'm saying.....will try one more time....

Volunteer calls up the form that will enter specimen data into a large database. They choose the genus and specie and by doing so, the elcode (special identifying text value) will pop up into the elcode field on the form along with some other data that is taken from the elcode table.

Is that clear?

Thanks for your  help to this point! one more question...why the heck do they use "me"? for the query?

    Dim db As Database, rst As Recordset, SQL As String
    Set db = CurrentDb
    ' SQL string.
    SQL = "Select * From YourTable Where genus = '" & Me!genus & "' AND specie = '" & Me!specie & "';"
    Set rst = db.OpenRecordset(SQL)
    Me!elcode = rst!elcode
    rst.Close
    db.Close
---------------------
OK first part opens the database where the Genus an Specie are then returns the elcode

DougP
dposton@universal1.com

Ask me how Bar-codes can help you be more productive.