What part of Mexico are you in? I've never even heard of such and I have spent a few months overall in Mexico.
Der Fish
Right now in Puebla. This is very common all over Mexico. The thing is obviously you won't see this in higher end restaurants, malls, etc...you have to get out onto the streets and hang out with the common folks. If you go to a fair for instance you'll see many people selling these.
This is indigenous cuisine.
In terms of tripe they use it in menudo, but you can also find it in other forms. For instance "Chistorra" - Fried entrails - is very common at steakhouses and some of the poshest restaurants as well.
Aguaita: Yes I have seen those as well. In addition you can find worms or other little critters in spicy "suckers" - Paletas.
The crickets were not bad at all. It tasted like a salty snack. The grasshoppers I didn't care for and the pulque either (slimy consistency).
I felt like Andrew Zimmern...:laugh: