A worldwide community photographing and learning about wildlife
Riptortus sp.
2cm long bug
I got the genus :)
Riptortus serripes is Australian, but R. linearis and R. pedestris have been reported in Sri Lanka.
http://www.forestryimages.org/browse/det...,
http://books.google.com.ph/books?id=5xvj....
The 5th instar looks like your bug - http://www.brisbaneinsects.com/brisbane_....
I could not find the matching genus, but this is a nymph from family Alydidae.