I think you are right. The open source dictionaries sometimes show 哈密瓜 as Honeydew. But when I have asked what it this called and pointed to a cantaloupe, people say 哈密瓜. Personally I think perhaps the native varieties are slightly different than what is in the US. And no the other varieties are there, but the old names persist.

I checked pleco and it shows the same as your dictionary. Google shows cantaloupe as 哈密瓜.