All of their email addresses are a standard format, providing you know their names:
For Texas House members, it is: firstname.lastname@house.state.tx.us
For Texas Senate members, it is:
firstname.lastname.senate.state.tx.us
Also, I might suggest that you not copy a letter that someone else sent word for word. Change it about a little and use your own style and terminology. Give it a litle more personal flair as opposed to having it look like just a form letter.
I sent out a pot full of emails Friday and followed those up with 26 regular letters yesterday.
-----
Gerald Keown
Southwestern Center for Herpetological Research