I was wandering down a street in the Seattle district in Guadalajara when I came across a vendor seiing pitayas.  They are the fruit of a Mexican cactus (Opuntia).  They are apparently very hard to harvest, which makes the fact that they sell for $0.10 each almost criminal.  They have a very delicate flavor and are best eaten raw.  The little black dots, by the way, are seeds and not bugs!   You can <a rel="nofollow" class="external text" href="http://www.mexconnect.com/mex_/travel/jrbaccon/jrbcactus.html">read more about it here</a>.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/94408886@N00">Samuel C. Blackman</a> from Jamaica Plain, MA, USA
CC BY 2.0
<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/94408886@N00/139206871/">Pitayas I</a>