From Eun Seo blog on thai foods
http://thailand-foods.blogspot.com/

You can read more at the food blog.

"Bamboo Caterpillar, Good for Your Brain

Rot Duan (รถด่วน) or bamboo caterpillar is an excellent menu which well-known among Thai. We can found it in fried-insect shop; grasshopper, weevil, cricket etc. Bamboo Caterpillar is different from another insect because it good class food, expensive, hard to find and nourishing your brain. It is one of 300 type of food in forest.

Rot Duan has many names up to its location if it lives in Northern called “Dae Pai or Dunag Pai”, in E-Gor tribe (เผ่าอีก้อ) called “Habolua”, in Karieng tribe (เผ่ากะเหรี่ยง) called “Kli-Kler” and Burmese called “Ju Sung”. Rot Duan is a grub of moth, family Pyralidae and it is a tropical insect zone found in Northern and North East of Thailand."