syntax

[Charles Bodley]

Is this the correct syntax to specify a MX record for a sub domain?
granted gloria.internal.tflogic.com will not respond it is internal.
Yet my dig response did not include this. the answer.
What I want is MX queries for *.dev.thinkingfolders.com to resolve to
gloria.internal.tflogic.com What would this syntax be?
Dig queary
dig @216.68.75.100 dev.thinkingfolders.com -t MX
Excerpts from zone file.
$ORIGIN .
$TTL 3600       ; 1 hour
thinkingfolders.com     IN SOA  thinkingfolders.com.
hostmaster.cyberset.com. (
                                2001101902 ; serial
                                43200      ; refresh (12 hours)
                                7200       ; retry (2 hours)
                                1209600    ; expire (2 weeks)
                                3600       ; minimum (1 hour)
                                )
                        NS      ns.tflogic.com.
                        NS      ns2.tflogic.com.
                        A       216.68.75.219
                        MX      5 mail.thinkingfolders.com.
                        MX      10 cyberset.com.

$ORIGIN dev.thinkingfolders.com.
$TTL 30 ; 30 seconds

login-a         A       216.68.75.194
login-b         A       216.68.75.202
                        MX      10 gloria.internal.tflogic.com.