It is not open to general admission. One may join the list by invitation only. ENT-LIST is maintained by Mark O'Brien of the University of Michigan. Discussion on this list is about insect systematics and curatorial matters. This is one of the best ent.listservers.
Discussion is on a variety of entomology-related topics.
You will get an automated welcome message from the server shortly thereafter. Archives are available. All members of the list will be added to the world wide directory of forensic entomologists, if desired. The address is uknown to me. This listserver is recently with no traffic at all.