Source:
http://www.musicwithease.com/harmonica-pictures.html
The acoustic structures of the harmonica are similar to a series of pipes connected in parallel, and thus functions like the panflute, accordion or pipe organ.
While the panflute does not have reeds, each "pipe" of the harmonica has a (typically) metal reed free on one side. Air blown through the "pipe" vibrates the metal reed, resulting in the Bernoulli effect.
Source:
http://www.musicwithease.com/harmonica-pictures.html
Source:
http://en.wikipedia.org/wiki/File:16-hole_chrom_10-hole_diatonic.jpg
The Chinese version of the harmonica, called the sheng, looks quite different and is also much larger. It is an ancient instrument, with pictorial evidence dating as far back as 1100 BCE. It is like a panflute with reeds, and thus similar to the western harmonica.
Source:
http://en.wikipedia.org/Sheng_(instrument).htm
http://www.soundsnap.com/tags/harmonica
http://www.silkroadproject.org/MusicArtists/Instruments/Sheng/tabid/328/Default.aspx