Photograph No1 & 2 adjacent to a paddy field and a small stream, at altitude 1000m. Bandung, W. Java.
Photograph No3 House flower garden, altitude 250m. Ciranjang village, Cianjur, W. Java.
I don’t get to see these stunning daytime moths very often, and so it is always a special day if I get to capture one in pixels. Image No3 actually shows egg laying in progress. I should have photographed the eggs while I was there, sorry.
Having said that ,there are two near identical species in your area.
The 2nd species is C. picus.
The definitive ID ,spines on the tibiae of the legs is near impossible to see.
However, the underside of the thorax & legs are tinged orange.
Clearly it was my best decision joining this forum. I just hope you don’t lose patience with me, as I soak up all this information and learning. With this moth, you rarely get to choose a shooting angle, but I will endeavour to get the underside and legs if possible in future.
Taking the images one at a time:
Image 1 – a good original and was able to crop in on the leg, showing the spines (image below). This makes the ID cephonodes picus.
Image 2 – shot from some distance and over exposed. The thorax underside and legs definitely look white, but this could be as a result of over exposure. I would say inconclusive and identify as cephonodes cf hylas.
Image 3 – Lots of pixels, slight over exposure, taken in bright sunlight. But, the orange under thorax and orange legs do show through, so ID cephonodes picus, as you stated.
If you agree with this conclusion, I will copy and paste into the lead post.