Weird Red Cicada-Like Moths

I have come across this insect many times in India, but I always found it hard to photograph them because they fly off at the very moment we come close to them. Their flight is also very creepy as they expose a white colour beneath their wings. However, during June, i was easily able to shoot these creatures. The one reason that allowed me to is... RAIN.
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These creatures tend to become very inactive after rain. They will just stad still or just turn around upon our approach. The rain, which makes them wet, seems to affect their usual habits of flying off easily.
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I'm not really sure what these insects exactly are. they are not cicadas despite their slightly similar look. They have not be known to make any sounds either. However, their movements are similar. I have not been able to identify this insect so for now I shall just call it the Cicada-Like Moth.

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They are usually found in groups. Some groups can even count upto 20 individuals! They are most commonly encountered on tree trunks a few feet above the ground, on the trunks of Rubber Trees in Rubber Estates (Which are very common in my area. Even my dad owns 10 acres of Rubber Estate there.)

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