Caraga Guitar made of bamboo

I had seen this in a published lecture from 1931 about Philippino musical instruments and "airs." Here's a picture from the Museum, of an example I saw today:

I was told that these instruments are still found today during festivals, and that when the festivities are over, they are thrown away. Holes are found at the ends and under the two strings, in what would be a sounding board. The following picture shows the holes at the end, and the binding around the instrument, the "nut" holding the bamboo fiber strip in tension and in position. The end with a hole is beaten with the open hand, like a drum, while at the same time the strings are plucked. This example is behind glass.

Caraga is the district including most of Northern Mindanao. The exhibit did not label this at all.