Yarchagumba  is actually a combination of one of Nepal's most famous flora and fauna. Caterpillar fungi are the result of a parasitic relationship between the larva of the ghost moth and the fungus Cordyceps sinensis. The fungus germinates within the larva of the ghost moth, killing and mummifying the insect.  Over time the fungus will grow out of the insect?s body and then grow into a small mushroom that can be used in many types of medicinal concoctions. Yarchargumba is a rare herb that is quite hard to find and difficult to harvest.  Yarchagumba is so valuable drugs and aphrodisiac. Yarchagumba has become one of the important economic source of  Rural Himalayan of Nepal. I have downloaded some pictures from google to make you understand  this ghost moth and fungus relationship.

source of image:google search