They are a type of termite and they appear every year around the start of rainy season. When the sun starts to set and lights start coming on, all the laron come out and swarm around any lights. Apparently they come out in search for a partner, and if they are not successful in their search, their wings quickly fall off and the poor little guys die within a couple of hours.
This is great for lizards, geckos, and monkeys. They all gather around the lights and have a feast. It's fun to sit and watch the lizards go wild eating all those bugs.It's not so great if you're eating dinner outside with lights on over your table. Literally hundreds of laron will converge on one lamp, so you're bound to get some of the bugs on your plate. This is the reason that many restaurants will just turn off their lights for the hour or so that the laron come out. I guess it's better to eat your food in the dark than to eat bugs in the light...
On a side note... Monkeys and lizards are not the only ones that enjoy eating laron. People like to gather them up and fry them for a crispy snack. They put big buckets of water under lamps in order to catch them (like in the picture on the right), then they drain them, then they fry them. Yum!