This insect is commonly called as Plant Hoppers. This is a Hemiptera(True Bugs, Cicadas, Hoppers, Aphids and Allies) in the family Flatidae from Insecta class of Animal kingdom. So we can easily call this insect as Flatid Planthoppers Nymph that has waxy tail filaments. I am not sure, but possibly this can be a gregarious insect as we found this at large number at one place.
This small creature is endemic to East Asia(Malaysia, Thiland, Indonesia, etc). But interestingly now it is seen from our Bandarban(বান্দরবান) hilly area too. It was beside the Ruma Khal(রুমা খাল), a trail between Boga Lake(বগা লেক) to Pukur Para(পুকুরপাড়া). We have found thousands of such insects over the plants around our trek. It looked like flowers were bloomed over those plants. So we almost ignored that. But someone from us noticed those moving, and initially thought as white spider. But after verifying from an expert, we have finally able to identify this beautiful insect.
Photo courtesy, Mahmudul Hassan Roby