Here are some more details on my bridging problem.  Here is a diagram
of the network topology:

wireless -------- bridge ------------------- gateway
host                              |
                                  |
                              wired host

The bridge network interfaces are configured as follows:

ifconfig -a (edited output)
ep0: flags=8963<UP,BROADCAST,NOTRAILERS,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
        address: 00:a0:24:ed:97:d0
        media: Ethernet 10baseT
        inet6 fe80::2a0:24ff:feed:97d0%ep0 prefixlen 64 scopeid 0x1
wi0: flags=8b63<UP,BROADCAST,NOTRAILERS,RUNNING,PROMISC,ALLMULTI,SIMPLEX,MULTICAST> mtu 1500
        nwid <ID> nwkey <KEY>
        powersave off
        address: 00:02:2d:3c:26:56
        media: IEEE802.11 autoselect
        status: active
        inet6 fe80::202:2dff:fe3c:2656%wi0 prefixlen 64 scopeid 0x9
bridge0: flags=41<UP,RUNNING> mtu 1500

brconfig bridge0
bridge0: flags=41<UP,RUNNING>
        Configuration:
                priority 32768 hellotime 2 fwddelay 15 maxage 20
        Interfaces:
                wi0 flags=3<LEARNING,DISCOVER>
                        port 9 priority 128
                ep0 flags=3<LEARNING,DISCOVER>
                        port 1 priority 128
        Address cache (max cache: 100, timeout: 1200):
                00:02:2d:7b:17:c3 wi0 208 flags=0<>
                00:08:e3:0f:59:09 ep0 126 flags=0<>

For simplicity I have severely truncated the address cache to include
only the two ethernet addresses for wireless host and the gateway in
the above diagram.  The complete list includes lots of others on the
wired network.

Pings from the wireless host to the gateway yield the following arp
traffic (selected from a long list of essentially identical packets),
but no entries in the arp table on the wireless host.  Note that the
wired host examining the network traffic is not the gateway being
pinged.

wireless host: tcpdump -n -e -i wi0 
08:50:09.430209 0:2:2d:7b:17:c3 ff:ff:ff:ff:ff:ff 0806 42: arp who-has 128.123.94.1 tell 128.123.95.225

bridge: tcpdump -n -e -i wi0 host 128.123.95.225
08:50:06.852332 0:2:2d:7b:17:c3 ff:ff:ff:ff:ff:ff 0806 42: arp who-has 128.123.94.1 tell 128.123.95.225
08:50:06.864851 0:8:e3:f:59:9 0:2:2d:7b:17:c3 0806 60: arp reply 128.123.94.1 is-at 0:8:e3:f:59:9

wired host: tcpdump -n -e -i fxp0 host 128.123.95.225
08:50:06.880870 0:2:2d:7b:17:c3 ff:ff:ff:ff:ff:ff 0806 60: arp who-has 128.123.94.1 tell 128.123.95.225

From all of this, I conclude the the bridge is passing packets in both
directions, and that the wireless hosts is generating proper arp
requests but is not receiving the responses.

- Is this the proper interpretation of these results?

- Is the bridge configured properly?

- How can I make this work correctly?

Thanks again for your help.

Cheers,
Brook