Signature spider, Writing spider, Orb-weaver spiders. 
Different name to suit the specimen. They are beautiful, widespread and strikingly colorful abdomen spiders. They belong to the Family Araneidae.
The very easily visible pattern of banded silk made by Argiope is pure white, and some species make an "X" form, or a zigzag type of web 
(often with a hollow center). The spider then aligns one pair of its legs with each of the four lines in the hollow "X," 
making a complete "X" of white lines with a very eye-catching spider colored bright yellow on a field of black or variegated red white and yellow stripes forming its center. The white patterns are called stabilimentum and reflect UV light.

This specimen was found at K.G.Chavadi (Coimbatore) on my way back from College to my hostel. These walks have always stuck me with interesting wildlife specimens of arachnids, avians, reptilians, amphibians etc.. and ofcourse.. loads of road-kills..

On 31 March 09, I found this specimen from under the culvert on PKD CBE Highway.. around 3:30 PM. This guy caught my attention from a long way. Was surprised to see such a big specimen of the species (Argiope anasuja). I had the ruler with me so that i could measure the him/ her 
(I dunno what sex it belonged). The measurement was surprising. 
I have seen and measured more than 15-20 specimen of Argiope anasuja and non gave this big measures.

length (From Abdomen to head) 
around 6Cm
Left leg (Hind) to right leg (Front) 
around 12Cm..

Huge it was.. I could also take some pictures of the specimen, 
which i have uploaded here.