The Melvins are currently a three piece, although the lineup beyond Buzz and Dale for a tour or album can change at any time. The current members are...
The Melvins formed in Montesano, WA in 1983 the founding members were Buzz, Mike Dillard (drums), and ex-Mudhoney bassist Matt Lukin. Buzz, Mike, and Matt all went to high school in Montesano. The name Melvins came from a Manager of the Thriftway grocery store in Montesano where Buzz served as clerk.
Mike Dillard left the band in 1984, Dale Crover shortly thereafter recruited out of the Iron Maiden cover band he played in and has been a member ever since. Matt was replaced by Lori Black (Lorax) (Shirley Temple's daughter) in 1988 when they left Washington for San Francisco, CA.
The Melvins have had quite a few bass player changes during their tenure. Check out the Melvins Bassist Morgue to learn more. The Melvins are currently based out of Los Angeles, CA.
The Melvins Discography is an exhaustive resource of their many releases. They were on a major label Atlantic Records for three albums, although most would agree they're not the type of band that would appeal to a major label. They are often quoted as knowing this while they were on the label and just took advantage of the drunken blitz the record companies were on in signing any band connected to a supposed Seattle "grunge" sound. Melvins have also released music on Ipecac Recordings, Boner Records, Alchemy Records, Amphetamine Reptile Records, Alternative Tentacles Records, and numerous other independent record labels over the years.
Buzz has a side project called Fantômas with Mike Patton (Faith No More/Mr. Bungle) who is also owner of Ipecac Recordings the label the melvins are currently releasing material through. He also played guitar in the hardcore/grind "supergroup" Venomous Concept, featuring members/former members of Napalm Death and Brutal Truth (also released through Ipecac).
Dale filled in for Nirvana when they were between drummers, he appears on Incesticide and Bleach as a result of those sessions. Dale has two major side projects one called Altamont in which he sings and plays guitar. The other he drums in and is known as PORN (The Men Of) or just PORN.
Melvins have toured with KISS, White Zombie, Nine Inch Nails, L7, Primus, Tool, and Rush, among others and were also on the Ozzfest tour in 1998. They toured with a second guitarist David Scott Stone from 2000-2003. Former bassist Kevin Rutmanis (1998 - early 2005) used to be in the band Cows, he was also in another Mike Patton project along with Duane Denison of the Jesus Lizard called Tomahawk. If you ever get the chance to see them live be sure to give them gifts, they prefer Cracker Barrel gift certificates.