Carter ventilation tubes(s) ??

[JDS82]

So there are 2 black tubes going into the punto airbox. One big and one small. The big one is for the Carter ventilation ( pcv valve) but i can not find anywhere on Google what the smal one is.. it goes down into the back of the engine. Can anyone tell me what this is for?

 

[JDS82]

It's the tube in the white circle. The black circle is the PCV valve that I know. So what is the function of the one in white circle?

 

[JDS82]

Nobody??